Invoker
* Zeus greatly hinders Invoker on the line with his long-range abilities. QW- and QE-Invoker have a very long recharge on abilities, and Zeus' 
Arc Lightning ability recharges too quickly, which is why he quickly kills a pack of creeps and drives Invoker under his tower, punching and not letting finish off creeps
* 
Lightning Bolt and 
Thundergod's Wrath abilities reveal invisibility of enemies, for example Invoker invisibility from 
Ghost Walk ability
Additional:
* Zeus greatly hinders Invoker on the line with his long-range abilities. QW- and QE-Invoker have a very long recharge on abilities, and Zeus' Arc Lightning ability recharges too quickly, which is why he quickly kills a pack of creeps and drives Invoker under his tower, punching and not letting finish off creeps
* Lightning Bolt and Thundergod's Wrath abilities reveal invisibility of enemies, for example Invoker invisibility from Ghost Walk ability
Legion Commander
* Heroes with global abilities can give Legion Commander's opponent an edge in Duels from anywhere on the map: 
Nature's Prophet, 
Ancient Apparition, 
Zeus, 
Invoker, 
Treant Protector
Invoker
* 
Bounty Hunter and 
Slardar both have ultimates (
Corrosive Haze and 
Track) that reveal Invoker through Ghost Walk.
Legion Commander
* With armor items like 
Solar Crest or 
Assault Cuirass combined with Bash of the Deep, Slardar can easily tank the 
Duel, If not dueled himself, he can drop 
Legion Commander's armor during duel and/or buff his teammate and save them, leaving her only the choice of dueling supports which can also be saved with fast Blink into Slithereen Crush.
Invoker
* Heroes with abilities which have a built-in spell immunity: 
Lifestealer, 
Juggernaut, 
Pangolier.
Legion Commander
* 
Lucky Shot can disarm Legion Commander and reduce her armor, which can reduce her chances of winning a duel. If an ally is targeted, Pangolier can simply use 
Swashbuckle to inflict it on her.
* If an enemy Pangolier casts a well-timed 
Rolling Thunder before Legion Commander can cast Duel, it might result in her chasing down Pangolier until his or her ultimate ends, whichever duration ends first, resulting in an open window for enemy allies to target Legion Commander, making her vulnerable and susceptible to any source of attacks. If Legion Commander has an 
Aghanim's Scepter in her inventory, the risk of wasting a solid 8 seconds would result in a futile duel.
* Dueling Pangolier is normally a mistake, Pangolier can disarm you in the duel, and potentially gain some Duel damage, Only duel Pangolier if at least 1 ally is nearby, and he is on low health, And even then, be wary, A good duel can easily turn against you with one Lucky Shot (Due to Lucky Shot lasting 4 seconds).
Additional:
* Swashbuckle can be used to disarm Legion Commander while she is Dueling an ally, granting her opponent a considerable advantage, Lucky Shot lasts 4 seconds at most wasting Legion Commander's entire Duel, (Or half, if Legion Commander has the Scepter).
* Legion Commander will try not to duel Pangolier alone, as she will almost inevitably lose, thanks to Lucky Shot's disarm, If Legion Commander wants to duel a Pangolier, she must be with atleast a teammate, and if she has her scepter, 3 or 4 teammates.
* Legion Commander is often with her allies, allowing you to rack up some considerable damage resistance with Shield Crash.
Invoker
* 
Astral Imprisonment allows Outworld Destroyer to save himself or ally from Invoker's combo, or remove Invoker from a fight temporarily.
* 
Arcane Orb's pure damage will deal a lot of damage against Invoker's mediocre strength gain.
* E.M.P. is useless against Outworld Destroyer by activating 
Equilibrium.
* However, be aware that 
Sanity's Eclipse will most likely not deal any damage at all, due to Invoker's high intelligence gain compared to Outworld Destroyer's.
Legion Commander
* Astral Imprisonment prevents Legion Commander from killing her opponents in Duels.
Additional:
* Outworld Destroyer can save an ally hero caught by Duel with Astral Imprisonment, and he can inflict heavy damage on Legion Commander with Arcane Orb to aid his ally. However, if he gets caught, he is unlikely to survive the duel, due to his lack of durability.
Invoker
* Any heroes with high intelligence, such as Invoker and 
Pugna.
Legion Commander
* If he isn't broken (break), Abaddon can use Borrowed Time to waste Legion Commander's Duel, As Borrowed Time has a shorter cooldown, Legion Commander can't win duels, effectively reducing her targets by one, Duel also means that Borrowed Time heals Abaddon for the duration of the duel, as Legion can't stop attacking.
Additional:
* 
Aphotic Shield and 
Mist Coil makes it hard for Legion Commander to kill Abaddon's teammates in Duels.
* 
Borrowed Time makes Abaddon nearly impossible to kill in Duels, and often replenishes much of his health because Legion Commander cannot manually stop attacking during Duels.
Invoker
* 
Rage grants immunity from Invoker's spells and can dispel most of the disables such as the armor loss from Forge Spirit and the constant stuns of Cold Snap.
Additional:
* Rage protects Lifestealer from all of Invoker's spells (except for 
Sun Strike).
Legion Commander
* 
Gravekeeper's Cloak protects Visage from Legion Commander's attacks for most of Duel's duration.
* Chain stuns from Visage's familiars prevents Legion Commander from winning Duels.
Invoker
* 
Crippling Fear is a good way to shut down and gank Invoker in the early game..
* 
Void deals good damage to Invoker and makes escaping harder.
* With 
Hunter in the Night and Void, Invoker can't get away from Night Stalker and won't be able to catch him with Sun Strike during the night.
Invoker
* Lone Druid has a very large reserve of health against Invoker abilities, this allows him to survive a large number of attacks from Invoker and kill him, also 
Entangling Claws reveal invisibility from Ghost Walk, which allows the Lone Druid team to catch the popular QW-Invoker
Additional:
* Lone Druid has a very large reserve of health against Invoker abilities, this allows him to survive a large number of attacks from Invoker and kill him, also Entangling Claws reveal invisibility from Ghost Walk, which allows the Lone Druid team to catch the popular QW-Invoker
Legion Commander
* Battery Assault's mini-stuns can severely disrupt Legion Commander's attack animation when she enters a Duel, potentially saving Clockwerk (or his allies) and possibly even giving him an edge in securing a win himself.
* Power Cogs pushes Legion Commander away from Clockwerk's allies when she enters a Duel.
Legion Commander
* Solar Guardian can save allies who are being dueled and will interrupt her Duel initiation.
Invoker
* Heroes that depend on disrupting fights with ability combos or big ultimate abilities are vulnerable to the long stun of Fiend's Grip: 
Disruptor, 
Death Prophet, 
Enigma, 
Faceless Void, Invoker, 
Lich, 
Magnus, 
Mars, 
Medusa, 
Outworld Destroyer, 
Phoenix, 
Puck, 
Queen of Pain, 
Shadow Fiend, Treant Protector, 
Underlord, 
Winter Wyvern, 
Witch Doctor, Zeus.
Legion Commander
* Bane has powerful single-target abilities that can help his allies win Duels, or at least cripple Legion Commander for the duration.
* Nightmare can waste Duel's entire duration as the dueled units transfer the Nightmare back and forth. This may be prevented if a non-Dueling unit attacks the Nightmared Dueler.
Additional:
* 
Enfeeble, 
Nightmare and 
Fiend's Grip all prevent Legion Commander from winning Duels, especially when Bane has 
Blink Dagger.
Legion Commander
* Heroes with strong dispels can dispel Bane's disables from their allies: 
Oracle, Legion Commander, 
Omniknight.
Legion Commander
* 
Fury Swipes can give Ursa the edge in Duels.
* 
Enrage's instant cast time allows it to be used before Legion Commander initiates a Duel, causing Ursa to take almost no damage for a brief period of time.
* However, Duel stops Ursa from casting Enrage at the most critical moment
Legion Commander
* 
Atrophy Aura's percentage-based damage reduction greatly diminishes Legion Commander's overall damage output, even if she has won many Duels
* Legion Commander cannot get out the way of Firestorm because she is stationary.
Additional:
* Atrophy Aura makes it hard for Legion Commander to win Duels.
* 
Fiend's Gate can be used to save Underlord and his allies from a Duel or to intercept Legion Commander, because outside from 
Overwhelming Odds, Legion Commander has no other area-of-effect abilities.
Legion Commander
* 
Paralyzing Cask can save ally from Legion Commander Duel's until she purchases Aghanim's Scepter.
* 
Voodoo Restoration can heal Witch Doctor allies from Duel's.
* 
Death Ward can help Witch Doctor allies from winning Duel's, if, he is not a target.
Invoker
* Puck Outlanes Invoker with his abilities: 
Illusory Orb, 
Waning Rift finishing off all creeps on the line and getting a higher level than him
* Puck dodges Invoker's magic attacks with his abilities: Illusory Orb, 
Phase Shift in a fight, preventing Invoker from doing damage
Additional:
* Puck Outlanes Invoker with his abilities: Illusory Orb, Waning Rift finishing off all creeps on the line and getting a higher level than him
* Puck dodges Invoker's magic attacks with his abilities: Illusory Orb, Phase Shift in a fight, preventing Invoker from doing damage
Legion Commander
* 
Mystic Flare can easily burst down Legion Commander while she is Dueling.
Invoker
* 
Tidebringer pressures Invoker easily in lane due to Invoker's low health and armor in the early game.
Legion Commander
* 
Static Link drains Legion Commander's accumulated damage, effectively neutralizing her overall primary advantage, and prevents her from winning Duels.
* 
Storm Surge's movement speed buff makes Razor and his allies harder to catch and initiate.
* 
Eye of the Storm, if used beforehand, will always hit Legion Commander during Duels, due to her forced proximity. This drastically lowers her survivability during Duel.
Invoker
* 
Doom completely takes Invoker out of a team fight, a hero who relies heavily on using abilities and items to contribute in team fights.
Additional:
* Doom is a good way to shut down Invoker, preventing from casting spells and using items for a lengthy time, thus forcing him to invest on 
Linken's Sphere.
Invoker
* Templar Assassin can easily counter Invoker's last hitting process in the early game with 
Refraction. Refraction also negates the stun from Cold Snap, since it will need to deal damage in order to apply its stun.
* Additionally, Refraction completely blocks damage from Sun Strike should Invoker try to finish her off, provided she activate Refraction beforehand.
Invoker
* Time Walk can easily avoid Invoker's combo damage if doesn't have disables.
* Chronosphere will reveal Invoker during Ghost Walk.
* All of Invoker's hidden cooldowns are affected by Time Dilation, so Faceless Void can easily slow him down a lot.
Additional:
* 
Time Dilation prevents Invoker from further invoking for the entire duration of the debuff, as well as massively slowing Invoker based on the large amount of spells he has.
* 
Time Walk will completely negate Invoker's combo damage.
* If Invoker is caught in 
Chronosphere, he will most likely be the primary target due to the large teamfight contribution he can provide.
Invoker
* Heroes with long lockdowns: 
Shadow Shaman, Legion Commander.
Legion Commander
* Heroes with long or multiple disables will prevent Legion Commander from winning Duels: Shadow Shaman, 
Lion
Legion Commander
* 
Pudge, Legion Commander and 
Axe will make the match a living hell for Shadow Shaman, since they are known for surprise attacks from the fog and quickly killing low HP heroes. They can also interrupt Shadow Shaman's channeling, Legion being especially problematic, as she can use 
Press the Attack on an ally who is hexed as well.
Legion Commander
* Heroes who can hide the Dueled target (Outworld Destroyer, 
Shadow Demon, 
Tusk, Phoenix with Aghanim's Scepter etc).
Additional:
* Legion Commander relies on her powerful attack and her Duel to be effective. But if Phoenix gets the jump on her first, she can find herself severely slowed, taking heavy damage, and find herself unable to Duel a burning Supernova.
* It must be noted that Press the Attack will both dispel the attack slow of Fire Spirits and grant her or whoever she targets bonus attack speed. This allows her to easily destroy a Supernova if caution is not taken to prevent this from occurring. As such, it would be a better decision to simply avoid a farmed or skilled Legion Commander instead of attempting to overpower her.
* If an ally is caught by Duel, Phoenix can use Sun Ray to heal the ally and damage Legion Commander, possibly swinging the Duel in their team's favor. Or with Aghanim's Scepter, Phoenix can save an ally from dying in Duel with Supernova and cancel the Duel as well.
Legion Commander
* Heroes who can hide the Dueled target (Outworld Destroyer, Shadow Demon, Tusk, Phoenix with Aghanim's Scepter etc).
Additional:
* Disruption can save allies and mess up an initiation from an enemy Legion Commander. Using Disruption on your ally that is affected by Duel will leave her totally exposed without the benefit of the life steal from 
Moment of Courage. A precise decision to Disrupt Legion Commander or her victim is crucial to waste Duel's potential.
* Demonic Purge cannot be dispelled by a hard dispel from Press the Attack, which in turn can be dispelled by your ultimate.
Legion Commander
* Heroes with global abilities can give Legion Commander's opponent an edge in Duels from anywhere on the map: Nature's Prophet, Ancient Apparition, Zeus, Invoker, Treant Protector
Legion Commander
* 
Troll Warlord's melee bash and high attack speed can often help him and his allies win Duels against Legion Commander.
Legion Commander
* Heroes who can hide the Dueled target (Outworld Destroyer, Shadow Demon, Tusk, Phoenix with Aghanim's Scepter etc).
Additional:
* Walrus PUNCH! makes Legion Commander lose Duel easily, especially when she doesn't have 
Blade Mail. Tusk can also snowball dueled allies, preventing them from taking damage for a large portion of the duel's duration.
Legion Commander
* 
Fate's Edict prevents Legion Commander from attacking for a few seconds, potentially saving Oracle's ally.
* 
Fortune's End dispels Press the Attack's healing and attack speed buff, as well as the movement speed bonus from Overwhelming Odds.
* 
False Promise protects allies and prevents Legion Commander from winning Duels and gaining bonus damage.
Additional:
* Provided that the enemy team does not have an Axe, Oracle can guarantee that his ally survives for the duration of the Duel with False Promise and has decent nuke potential to help ally to win a Duel. He can also disarm Legion Commander with Fate's Edict.
* Oracle can dispel enemy buffs like Overwhelming Odds and Press the Attack with Fortune's End.
Legion Commander
* Heroes with long disables, like Lion, 
Night Stalker, or Legion Commander, can prevent Oracle from using spells or items.
Invoker
* A good choice against Invoker, as it has some advantage with the help of abilities.
* With the 
Dissimilate, Voidspirit can evade Invoker's skills, going to another world where he does not receive damage. The same ability to run away or attack quickly.
* 
Astral Step moves quickly from point to point, which also reduces the Invoker's probability that he will hit him with skills and cause at least some damage.
Additional:
* A good choice against Invoker, as it has some advantage with the help of abilities.
* With the Dissimilate, Voidspirit can evade Invoker's skills, like 
Chaos Meteor or 
E.M.P., going to another world where he does not receive damage. The same ability to run away or attack quickly.
* Astral Step moves quickly from point to point, which also reduces the Invoker's probability that he will hit him with skills and cause at least some damage.
Legion Commander
* Special mention to Legion Commander, as she can lock down Void Spirit for a long amount of time without worrying too much about being killed by him during the Duel.
Invoker
* Invoker is heavily dependent on his spells, making him useless during 
Global Silence, as well as interrupting Invoker during his combo.
* 
Arcane Curse is particularly deadly, because Invoker will continuously lose health if he keeps invoking and casting new spells.
* 
Last Word will silence Invoker when he casts Invoke, interrupting his combo.
Legion Commander
* Heroes that can disable or silence Silencer for a long time, such as 
Bane and Legion Commander, can lock down Silencer while their allies put him down.
Legion Commander
* When Legion Commander uses Duel on one Meepo, he can use his other Meepos to kill her. If he wasn't dueled, he can help the teammate who was duelled to give the teammate the damage instead of Legion Commander.
* However, if Legion Commander picked up an Aghanim's Scepter and she duels one Meepo, that might be the end of Meepo if Legion managed to gather enough damage from previous duels.
Invoker
* Heroes with powerful area-of-effect disables can initiate on Meepo and his clones and shut him down, such as Enigma, Invoker, Magnus, Puck, and 
Sand King.
Legion Commander
* 
Purification prevents Legion Commander from killing her target, and will always hit her during Duels.
* 
Guardian Angel completely wastes Duel's duration and can save an ally across the map when upgraded with Aghanim's Scepter.
Additional:
* Both Guardian Angel and Purification are perfect counters against Duel.
Invoker
* Heroes with naturally low mana can be easily shut down by E.M.P.: 
Sven, 
Tiny, 
Wraith King, Omniknight
Additional:
* 
Tornado dispels Heavenly Grace and Guardian Angel from multiple targets.
* Guardian Angel is generally useless against Invoker as he primarily relies on magical damage.
* E.M.P. depletes Omniknight's already small mana pool.
* Invoker's many disables keep Omniknight's team occupied until Guardian Angel times out.
Invoker
* Earth Spirit is a dangerous foe to encounter for Invoker in the early stages of the game. Since Invoker needs to gain levels as fast as possible and is not very strong in the early game, Earth Spirit can use his incredible early game power to gank Invoker and ruin his game plan.
* Earth Spirit combines stuns and silences with his spells and can apply them from a great distance. This is bad for Invoker as he is dependent on a smart usage of his spells with 
Invoke and Earth Spirit can disrupt his combos easily.
Legion Commander
* Heroes rely on their debuff to control the opponent will have a hard time against Press the Attack: 
Venomancer, 
Earth Spirit, 
Ogre Magi
Legion Commander
* Earthshaker's AoE stuns can save ally against Duel, forcing Legion Commander to spend Aghanim's Scepter or 
Black King Bar.
Invoker
* Invoker's E.M.P. is extremely effective against Earthshaker due to his low natural mana.
Invoker
* In the early to mid game, Invoker is defenseless against Storm Spirit's ganking with 
Ball Lightning and 
Orchid Malevolence.
Invoker
* Heroes with mana burn: 
Nyx Assassin, Invoker, Outworld Destroyer, Pugna, Lion
Legion Commander
* A well-timed 
Eclipse before a Duel usually prevents Legion Commander from winning Duels, if Luna is the target.
* Meanwhile, when Luna is not a target, Eclipse and 
Lucent Beam can also help an ally win a Duel against Legion Commander.
* However, skilled Legion Commander will always buy a Black King Bar to block Eclipse and Lucent Beam or Aghanim's Scepter to reduce it's damage.
Additional:
* A well-timed Eclipse before a Duel usually prevents Legion Commander from winning Duels if Luna is the target. Luna can also buy Linken's Sphere to block Duel.
* Meanwhile, when Luna is not a target, Eclipse and Lucent Beam can also help an ally win a Duel against Legion Commander.
* Bear in mind, however, that skilled Legion Commander will always buy a Black King Bar to block Eclipse and Lucent Beam or Aghanim's Scepter to reduce their damage.
Legion Commander
* Heroes that can keep Luna locked down for a long time can be a threat (she is very item and spell dependent): Faceless Void, Legion Commander, 
Doom.
Legion Commander
* 
Shallow Grave prevents Legion Commander from killing her opponents in Duels.
* 
Shadow Wave will heal an ally caught in a Duel, as well as dealing damage to Legion Commander.
Invoker
* Some heroes with extreme range, like Zeus, Invoker or 
Clockwerk, can snipe your allies from anywhere after your Grave has expired.
Legion Commander
* Song of the Siren lasts long enough to prevent a successful Duel (but only if Naga wasn't the target).
Legion Commander
* Heroes who rely on illusions will see them destroyed easily by Overwhelming Odds: 
Phantom Lancer, 
Chaos Knight, 
Terrorblade, 
Naga Siren
Legion Commander
* 
God's Strength makes Sven one of the worst heroes to Duel.
* 
Storm Hammer can be used to interrupt Duels.
* 
Warcry gives a big boost in passive defensive ability with the active component to nearby allies.
* With the Aghanim Shard Warcry also gives nearby allies passive increases.
Invoker
* Heroes with naturally low mana can be easily shut down by E.M.P.: Sven, Tiny, Wraith King, Omniknight
Invoker
* Heroes with silence: Death Prophet, 
Riki, 
Drow Ranger.
Legion Commander
* Heroes with abilities that blind or cause Legion Commander to miss will prevent her from winning Duels: 
Arc Warden, 
Keeper of the Light, Riki, 
Tinker
Legion Commander
* Another great threat to Riki since her Duel forces him to fight from the front and expose him for the entire duration, almost always guaranteeing an easy win (unless Riki has allies helping him).
* Moment of Courage can become hard to deal with as it doesn't cease with silence.
Invoker
* QW-Invoker perfectly resists Batrider in his attacks, since Batrider has a small mana reserve and depends very much on him - E.M.P. perfectly allows Invoker to deprive her, and he also has the abilities of Tornado and 
Cold Snap, which can help him fend off his attack, and possibly even kill along with his team
Additional:
* QW-Invoker perfectly resists Batrider in his attacks, since Batrider has a small mana reserve and depends very much on him - E.M.P. perfectly allows Invoker to deprive her, and he also has the abilities of Tornado and Cold Snap, which can help him fend off his attack, and possibly even kill along with his team
Legion Commander
* Press the Attack dispels Flaming Lasso.
* Batrider is unlikely to win a Duel in any stage of the game.
Invoker
* Invoker's arsenal of magical spells are troublesome for Sniper who has low HP and high armor, which does not benefit him much against Invoker.
* Besides magical damage, he can be disarmed and repeatedly mini-stunned with Cold Snap, preventing him from reacting.
* Leveling 
Quas can allow Invoker to lane effectively against Sniper despite right-click harassment.
Legion Commander
* Sniper's low mobility and lack of defensive abilities make him an easy gank target for the entire game, especially if Blink Dagger is picked up.
Invoker
* Heroes who can summon illusions and summons because Terrorblade has no abilities to deal with multiple enemies at once outside Reflection: Shadow Shaman, Naga Siren, 
Broodmother, 
Lycan, Enigma, Chaos Knight, Phantom Lancer, Shadow Demon, 
Dark Seer, Nature's Prophet, Invoker, 
Morphling, 
Visage, 
Grimstroke with Aghanim's Scepter.
Legion Commander
* Duel's long duration prevents Terrorblade from swapping his health with 
Sunder.
* Overwhelming Odds deals high damage to Terrorblade's illusions.
Invoker
* Quas Exort Invoker has high physical damage in the form of Cold Snap and Forged Spirits that allows him to trade hits with Huskar.
* Although Huskar can dispel Cold Snap with Life Break.
* Sun Strike deals pure damage and pierces spell immunity, and Huskar tends to drain his HP, making him a susceptible target.
Legion Commander
* Carries that can out damage Huskar will do well against him: Legion Commander, Faceless Void, Troll Warlord, 
Phantom Assassin.
Additional:
* 
Life Break is almost suicidal when used on Legion Commander, as it invites an instant Duel and Legion Commander herself is a natural Blade Mail carrier.
* Huskar's low survivability and mostly on low health make him particularly vulnerable to Legion Commander's high physical damage.
Legion Commander
* Press The Attack can save her allies dispels the stun from Shackleshot.
* Duel can lock down Windranger before she can escape with Windrun.
* Legion Commander tends to go for Blade Mail, which returns the damage she takes from Focus Fire.
Legion Commander
* Chen's fragility and low mobility make him an enticing Duel target.
* Overwhelming Odds and Moment of Courage can take advantage of converted creeps's numbers.
* With enough damage from Duel stacks, Legion Commander can also often kill any of Chen's unfortunate allies before he can use Hand of God.
Additional:
* Chen's frailty and low mobility make him an enticing Duel target.
* Overwhelming Odds and Moment of Courage can take advantage of converted creeps' numbers.
* With enough damage from Duel stacks, Legion Commander can also often kill any of Chen's unfortunate allies before he can use 
Hand of God.
Legion Commander
* Duel makes Bristleback fight Legion Commander face to face, forcing him to take full damage.
* Press the Attack dispels the slow from stacks of Viscous Nasal Goo.
Additional:
* When dueled, Bristleback will have to face Legion head on, not allowing his passive 
Bristleback to come into effect.
Invoker
* Cold Snap can prevent Timbersaw from using both Timber Chain and Chakram due to the frequent stuns interrupting the lengthy cast animations, as well as stopping him mid-chain. This can negate Timbersaw's attempts to escape or dole out extra ability damage.
* Later in the game, Invoker's heavy magical and pure damage can be difficult to avoid, meaning Timbersaw's armor is less useful.
Legion Commander
* Duel's long duration prevents Weaver from activating 
Time Lapse or escaping with 
Shukuchi.
Invoker
* Invoker's numerous area-of-effect abilities can interrupt Primal Beast, especially while he is in the middle of a team fight, where Primal Beast thrives. (Tornado, Cold Snap, and 
Ice Wall all help to disable Primal Beast and control him from a distance.
* E.M.P. disintegrates Primal Beast's low mana pool.
* However, Invoker is quite a slow-paced hero and not particularly known for being survivable against a rampaging Primal Beast with Black King Bar.
Invoker
* Ember Spirit has a small mana pool, which is why QW-Invoker can burn it out very effectively with his own E.M.P., do not give Ember Spirit the opportunity to play with his abilities and cause damage with them in a fight.
* QW-Invoker Destroys Ember Spirit's 
Flame Guard with his own Tornado, which is why Ember Spirit cannot defend against Invoker's strong magic damage.
Additional:
* Ember Spirit has a small mana pool, which is why QW-Invoker can burn it out very effectively with his own E.M.P., do not give Ember Spirit the opportunity to play with his abilities and cause damage with them in a fight.
* QW-Invoker Destroys Ember Spirit's Flame Guard with his own Tornado, which is why Ember Spirit cannot defend against Invoker's strong magic damage.
Legion Commander
* Legion Commander can use Press the Attack on an ally to dispel Dismember. The bonus health regeneration also partially counters the damage of Rot
* Duel can be used on Pudge whilst Rot is active, disabling toggling which may result in a lethal health drain that leaves Legion Commander with a successful duel.
Invoker
* Invoker is a big problem for Tiny the whole game because of its multiple disables. For example, the Cold Snap ability can catch an attack from Tiny's hand by surprise, because it becomes slower with the pumping of 
Grow. has a giant deceleration, creating a condition for the kite, which Tiny is very afraid of. In addition, Invoker has a 
Deafening Blast that disables Tiny's main weapon - strong blows from the hand
Additional:
* Invoker is a big problem for Tiny the whole game because of its multiple disables. For example, such as Tornado + E.M.P. create unrealistic conditions for Tiny with mana, which is very necessary for Tiny at least for some attacks in a fight. The Cold Snap ability can catch an attack from Tiny's hand by surprise, because it becomes slower with the pumping of Grow. has a giant deceleration, creating a condition for the kite, which Tiny is very afraid of. In addition, Invoker has a Deafening Blast that disables Tiny's main weapon - strong blows from the hand
Legion Commander
* Duel is a great initiation to target Crystal Maiden with, as it prevents her from using Freezing Field or any other abilities and allowing the enemy team to quickly kill her before she can aid her team in a fight.
Legion Commander
* 
Searing Arrows and Clinkz physical damage items are almost suicidal when used on Legion Commander, as it invites an instant Duel and Legion Commander herself is a natural Blade Mail carrier.
* Duel locks down Clinkz for a long duration, preventing him from escaping with 
Skeleton Walk.
Invoker
* Tornado allows Invoker to purge Necrophos's 
Ghost Shroud, nullifying any benefits he could get out of it
* E.M.P. allows Invoker to burn Necrophos's mana, preventing him from using his abilities constantly
Invoker
* 
Corrosive Skin makes Viper receive less damage from Invoker's spells
* Viper can harass Invoker with his 
Poison Attack in the early game.
* 
Viper Strike and Poison Attack can kill Invoker easily if Ghost Walk is on cooldown.
Invoker
* Ice Wall and Ghost Walk can be used to kite and escape from Viper.
* Chaos Meteor and Sun Strike deal heavy damage and can quickly bring Viper down.
* Cold Snap, Tornado, and Deafening Blast are powerful disables that reduce Viper's effectiveness.
* E.M.P. burns Viper's limited mana pool, reducing his potential poison damage.
* 
Forge Spirits can melt Viper's armor and reduce his durability.
Legion Commander
* Viper's frailty and low mobility make him an enticing Duel target and Corrosive Skin doesn't protect him against Legion Commander physical attacks.
* Press the Attack can dispel Poison Attack.
* Viper slows can easily negate by Overwhelming Odds movement speed.
Invoker
* Quas-
Exort Invoker can win the mid lane easily against Alchemist because Quas regeneration will nullify Acid Spray's damage over time and Exort damage bonus will allow Invoker to out last hit Alchemist.
Invoker
* Ice Wall can slow down 
Charge of Darkness in its tracks at max level, allowing counterplays such as Cold Snap to end the charge, bursting down with Tornado, Meteor, and right clicks, or even teleporting back to spawn to drag Spirit Breaker into the fountain.
* Cold Snap (if timed right) and Invoker's other disables like Tornado can interrupt Charge of Darkness, especially since Charge is telegraphed by the symbol appearing over head.
Additional:
* Cold Snap allows Invoker to interrupt Charge of Darkness and Nether Strike.
* Tornado's long range can be used to cancel Charge of Darkness.
* Deafening Blast prevents Spirit Breaker from right clicking and thus proccing his Greater Bash.
Invoker
* Any hero with a low HP pool is easy for Tinker to nuke down: 
Crystal Maiden, 
Enchantress, 
Gyrocopter, Lion, Riki, 
Techies, Terrorblade, 
Necrophos, Invoker.
Legion Commander
* Heroes with abilities that blind or cause Legion Commander to miss will prevent her from winning Duels: Arc Warden, Keeper of the Light, Riki, Tinker
Invoker
* Tinker is relatively helpless against Invoker, as his 
Rearm and 
Boots of Travel can be easily interrupted by Invoker's long range disables, even if he blinks away.
Legion Commander
* Press the Attack can dispel Laser's blind while providing great attack speed and health regeneration.
* Once caught in a Duel, Tinker, who completely relies on his spells to be effective, has little chances of survival with his low health pool and armor.
Legion Commander
* Heroes with low health will die easily during Duels, and can be farmed for damage in the early game: Crystal Maiden, Lich, Techies, 
Rubick
Legion Commander
* Heroes who rely on illusions will see them destroyed easily by Overwhelming Odds: Phantom Lancer, Chaos Knight, Terrorblade, Naga Siren
Additional:
* Overwhelming Odds deals high damage to Phantom Lancer's illusions.
* Duel's long duration prevents Phantom Lancer from using Doppelganger.
Legion Commander
* Heroes with strong area damage to destroy Phantasm illusions: Axe, 
Ember Spirit, Legion Commander, Phoenix
Legion Commander
* Heroes with low health will die easily during Duels, and can be farmed for damage in the early game: Crystal Maiden, Lich, Techies, Rubick
Invoker
* Any hero who can counter-initiate in anticipation without getting caught in Reverse Polarity: Sven, Omniknight, Enigma, 
Luna, Naga Siren, Mars, 
Jakiro, Venomancer, 
Elder Titan, Faceless Void, Rubick, Keeper of the Light, Pugna, Invoker, 
Spectre, 
Alchemist, Treant Protector, 
Lina, Oracle, Zeus, Shadow Shaman, Phoenix, 
Razor, 
Huskar, 
Batrider, 
Kunkka, 
Tidehunter, Wraith King, Sand King, Medusa, 
Dawnbreaker.
Invoker
* Heroes with long animations can be frequently interrupted with Cold Snap: 
Earthshaker, 
Monkey King, Shadow Fiend Lina
Invoker
* Heroes with long animations can be frequently interrupted with Cold Snap: Earthshaker, Monkey King, Shadow Fiend Lina
Legion Commander
* Heroes rely on their debuff to control the opponent will have a hard time against Press the Attack: Venomancer, Earth Spirit, Ogre Magi
Additional:
* Press the Attack dispels Venomous Gale and Poison Sting from Legion Commander or her teammates.
* Venomancer is an ideal target for Duel due to his lack of mobility and low starting health.
Invoker
* Heroes that can keep Marci for a long time in one place so she can't pursue her targets, like Bane, Lion, Shadow Shaman, Invoker, Disruptor and Kunkka.
Legion Commander
* Heroes who rely on summons will see them destroyed easily by Overwhelming Odds: Lycan, Arc Warden, 
Warlock, 
Chen
Legion Commander
* Magnetic Field prevents Legion Commander from getting wins with Duel.
Additional:
* 
Magnetic Field prevents Legion Commander from easily gaining wins with Duel.
Invoker
* Invoker's Forge Spirit can negate 
Flux.
* Provided he does a right combo with Chaos Meteor, Invoker can easily burst down Arc Warden (plus his clone if he spawns it.)
* An early Orchid Malevolence can shut down Arc Warden pretty hard, especially when Invoker has a good lane against him if he kills him early on.
* Deafening Blast and Ice Wall limit's Arc Wardens mobility and damage, crippling him greatly.
Legion Commander
* Heroes who rely on summons will see them destroyed easily by Overwhelming Odds: Lycan, Arc Warden, Warlock, Chen
Invoker
* Invoker's multiple spells can lock down Undying and disable him from doing much.
Legion Commander
* 
Tethered heroes are much harder for Legion Commander to kill in Duels.
* 
Relocate can cancel Duels and save allies.
Invoker
* Heroes whose abilities can affect multiple enemies at once: Dawnbreaker, Ember Spirit, Lina, Luna, Jakiro, 
Leshrac, Invoker, 
Muerta, 
Dazzle.
Legion Commander
* Duel is very effective against Io due to its low health and armor.
Legion Commander
* Heroes who rely on summons will see them destroyed easily by Overwhelming Odds: Lycan, Arc Warden, Warlock, Chen
Legion Commander
* Heroes rely on their debuff to control the opponent will have a hard time against Press the Attack: Venomancer, Earth Spirit, Ogre Magi
Legion Commander
* Long lockdown is a great way to deal with Axe to prevent Berserker's Call from being used, heroes such as Legion Commander, 
Beastmaster and 
Primal Beast are good examples of this.
Legion Commander
* Heroes with low health will die easily during Duels, and can be farmed for damage in the early game: Crystal Maiden, Lich, Techies, Rubick
Legion Commander
* Heroes with abilities that blind or cause Legion Commander to miss will prevent her from winning Duels: Arc Warden, Keeper of the Light, Riki, Tinker
Legion Commander
* Press the Attack can dispel Blinding Light or Solar Bind from a hero.
* Duel can be used to instantly take Keeper of the Light out of a team-fight.
Legion Commander
* Wraith King's 
Reincarnation allows him to severely punish Legion Commander after he revives, as her abilities are on cooldown. Legion Commander is still awarded a Duel win if Wraith King reincarnates.
Additional:
* Wraith King makes a poor Duel target, as he can be already quite hard to bring down once, and then you have to worry about his second life.
* However, even if Legion Commander does win the duel when Reincarnation is off cooldown, she still receives the permanent victory damage bonus because taking down Wraith King's first life still counts as a "kill".
Invoker
* E.M.P. allows Invoker to burn Wraith King's mana to prevent Reincarnation from triggering (only until Wraith King gets his Aghanim's Shard).
* Ice Wall and Cold Snap are particularly crippling for Wraith King as they allow to kite him very effectively, preventing him from dealing melee attack damage.
Additional:
* Invoker can drain Wraith King's mana with E.M.P., preventing him from reincarnating unless Wraith King has his Aghanim's Shard.
* Even if Wraith King survives and reincarnates, Invoker still has an arsenal of spells to lockdown Wraith King, including an easily setup Ice Wall.
* Tornado applies an area dispel to clear skeletons.
Invoker
* Heroes with silence: Death Prophet, Riki, Drow Ranger.
Legion Commander
* Drow Ranger's low mobility and lack of defensive abilities make her an easy gank target in the early to mid-game.
* A Dueling Drow Ranger will lose her precious 
Marksmanship, reduce her damage output significantly, and will more likely lose that Duel.
Legion Commander
* Because Duel requires both combatants to face each other, 
Bulwark's effectiveness will be increased by a huge margin, which makes it much more difficult for Legion Commander to win any duels against him.
* 
Spear of Mars and 
God's Rebuke pushes Legion Commander away during Duels against allies.
Additional:
* Bulwark immensely mitigates Duel, even with bonus physical damage, as Bulwark scales by percentage. Mars can also buy time for a dueled ally by pushing Legion Commander away with Spear of Mars.
Invoker
* Heroes with high magical or pure damage will bypass Bulwark: 
Timbersaw, 
Dark Willow, Enigma, Invoker, Pugna, 
Skywrath Mage, Tinker, Zeus, Oracle.
Legion Commander
* Legion Commander is both good and bad vs Mars, on the plus side she can dispel Spear of Mars with Press the Attack and is a good 
Silver Edge carrier. However, Mars is not an ideal Duel target, as Bulwark will force her to 1: Buy Silver Edge, and 2: Hit Mars with it before the Duel, allowing a skilled Mars to react, especially with 
Eul's Scepter of Divinity. In teamfights, Mars will happily draw attention after using his abilities, and tank the Duel with all spells on cooldown.
Legion Commander
* Heroes that cannot move in fights such as a Dueling Legion Commander or anyone channeling a spell like Bane, Pudge, or Enigma are easy Sacred Arrow targets.
Legion Commander
* Heroes that can protect or dispel stunned allies such as Legion Commander, Outworld Destroyer, Shadow Demon and Oracle can reduce the effectiveness of Sacred Arrow.
Legion Commander
* Heroes with global abilities can give Legion Commander's opponent an edge in Duels from anywhere on the map: Nature's Prophet, Ancient Apparition, Zeus, Invoker, Treant Protector
Legion Commander
* Legion Commander's Overwhelming Odds deals damage for every Treant it hits, which allows it to easily wipe out large waves of them.
Legion Commander
* Heroes that lack burst damage will have a difficult time taking down Monkey King, and fare badly against Jingu Mastery: Legion Commander, Lifestealer, 
Weaver, Wraith King
Invoker
* Heroes with long animations can be frequently interrupted with Cold Snap: Earthshaker, Monkey King, Shadow Fiend Lina
Invoker
* Anti-Mage's mobility and magic resistance make him nearly impossible to kill alone.
* Invoker's spells cost a lot of mana, and Invoker himself has a lot of mana. This means Invoker and his team are vulnerable to 
Mana Void's heavy damage.
* 
Blink allows Anti-Mage to escape from Invoker's combo if he doesn't have disables.
Legion Commander
* Duel renders Anti-Mage's escape capabilities with Blink and Counterspell useless. Blade Mail and Moment of Courage work well against Anti-Mage's relatively low health.
* A good initiation from Legion Commander and her team is enough to effortlessly kill Anti-Mage.
Additional:
* 
Counterspell offer no protection against Duel at all.
* Duel locks down Anti-Mage for a long duration, preventing him from escaping with Blink. One successful Duel initiation is usually enough for Legion Commander's team to kill Anti-Mage.
Invoker
* Queen of Pain usually outlanes Invoker, giving her team a significant early game advantage while Invoker is still farming.
* 
Blink allows Queen of Pain to escape from Invoker's combo if he doesn't have disables.
Legion Commander
* Duels prevents Queen of Pain from using Blink, which may force her to purchase a Linken's Sphere
* Because Queen of Pain is also not a right-click hero, Legion won't have much difficulties in duels.
* Press the Attack dispels Shadow Strike's debuff.
Legion Commander
* Heroes with long or multiple disables will prevent Legion Commander from winning Duels: Shadow Shaman, Lion
Legion Commander
* Lion is extremely dependent on his abilities. Silences like 
Silencer's Last Word, magic resistance like Oracle's Fate's Edict, and dispels like Legion Commander's Press the Attack all make his abilities less effective.
Invoker
* Quas-Exort Invoker is also a good matchup due to the fact he has no 
Wex to run faster due to the movement impairment on his stealth. The Forge Spirit and Cold Snap combo doesn't harm her as well since you can drain Invoker's HP with Spirit Siphon which forces him to retreat.
* Silence also prevents Invoker from using Invoke or casting his main spells temporarily. There is no way Invoker can block it unless he has Eul's Scepter of Divinity to cyclone himself or has help from allies.
Legion Commander
* Duel is a great initiation to kill Death Prophet before she can cast Exorcism. Furthermore, Legion Commander often builds Blade Mail and can reflect Exorcism's damage to kill Death Prophet easily.
Legion Commander
* Heroes with global abilities can give Legion Commander's opponent an edge in Duels from anywhere on the map: Nature's Prophet, Ancient Apparition, Zeus, Invoker, Treant Protector
Invoker
* Heroes with silence and mana drain abilites, as Ancient Apparition relies entirely on his abilities: Invoker, Silencer, Nyx Assassin, Skywrath Mage, Shadow Shaman, Lion and etc.
Invoker
* Nyx Assassin can simply activate 
Spiked Carapace while under many Invoker's abilities to stun him.
* Nyx Assassin takes advantage of Invoker's massive intelligence gain to do tons of damage using 
Mind Flare, as the spell does more damage based on the target's intelligence.
* 
Vendetta burns a large amount of Invoker's essential mana pool.
Legion Commander
* Duel's long duration prevents Nyx Assassin escaping from Vendetta. With Aghanim's Scepter, she can also bypass Spiked Carapace.
Legion Commander
* Enigma can be a perfect counter-initiator with his ultimate. A perfectly timed Black Hole will turn the tide of any initiation, especially from heroes like; 
Spirit Breaker, Legion Commander, Axe, Puck, and Slardar.
Invoker
* Heroes who can clear the waves of Enigma's Eidolons: Lina, Luna, Dawnbreaker, Jakiro, Shadow Shaman, Death Prophet, Keeper of the Light, Invoker, Leshrac, Puck.
Invoker
* 
Blade Fury, similar to Rage, grants immunity to Invoker's spells and can dispel some debuffs as well.
* 
Omnislash renders Juggernaut invulnerable to Invoker's spells and can easily take Invoker down.
Additional:
* Juggernaut's instant spell immunity from Blade Fury. helps him dodge Invoker's combos. He can dispel the disables from Cold Snap and Deafening Blast and dodge the damage from Chaos Meteor, as well as walk through Ice Wall.
* Juggernaut's high DPS allows him to kill split pushing Forge Spirit(s) effortlessly, and his high armor prevents them from being a threat to him.
* However, Invoker can hit Juggernaut with Sun Strike through Blade Fury, making the Tornado and Sun Strike combo a threat if he does not dodge Tornado.
Legion Commander
* Duel pierces spell immunity and forces him to attack Legion Commander, making him unable to use Omnislash.
Legion Commander
* 
Cold Embrace saves allies from dying in Duels.
* 
Winter's Curse turns Legion Commander's high damage against her allies, giving the enemy team little time to react.
* However, Winter Wyvern lanes very poorly against Legion Commander due to Press the Attack removing all the debuffs she can give. Winter Wyvern also has little chances of surviving if she gets Dueled herself.
Additional:
* Cold Embrace is very effective against Duel.
* Also, casting Winter's Curse at Legion Commander while an ally is in a Duel will stun her for most of the duration, possibly preventing lethal damage dealt to your ally. It can also turn her high-damage against her teammate.
Invoker
* Cold Embrace is the perfect setup for all his nukes - Chaos Meteor, E.M.P. and especially global Sun Strike.
Invoker
* Broodmother can kill Invoker easily in the early game with her 
Spawn Spiderlings and her spiderlings.
* Broodmother is both an Orchid Malevolence and a 
Nullifier carrier. As she can farm it early, she can kill Invoker easily.
Legion Commander
* Overwhelming Odds's damage stacks with each enemy unit in its radius. If this hits Broodmother and a large number of spiders it can deal significant amounts of damage.
* Moment of Courage has a high chance to proc if Broodmother and all of her spiders are attacking her.
* Duel can keep Broodmother in place long enough for Legion's team to kill her.
Additional:
* Overwhelming Odds is great at killing many stacked up spiderlings, thus giving Legion Commander a large buff.
* Duel is a reliable way to lock down Broodmother, preventing her from running into the treeline.
Invoker
* Bounty Hunter and Slardar both have ultimates (Corrosive Haze and Track) that reveal Invoker through Ghost Walk.
Legion Commander
* Legion Commander with Press the Attack
* Heroes that can remove the Track debuff with their skills:
* 
Abaddon with Aphotic Shield and Borrowed Time
* Huskar with Life Break
* Juggernaut with Blade Fury
* Legion Commander with Press the Attack
* Lifestealer with Rage and 
Infest
* Naga Siren with 
Mirror Image
* Omniknight with 
Heavenly Grace
* Oracle with Fortune's End and False Promise
* Phantom Lancer with 
Doppelganger
* 
Slark with 
Dark Pact
* 
Ursa with Enrage
* Weaver with Time Lapse
* Tidehunter with 
Kraken Shell when damage received reaches the threshold.
Legion Commander
* 
Mana Shield makes Medusa very hard to take down in Duels.
* 
Stone Gaze stops Legion Commander from Dueling altogether, regardless of who she targets.
Invoker
* E.M.P. allows Invoker to burn Medusa's mana to weaken Mana Shield.
* Medusa's lack of mobility makes her easy to kite with Invoker's spells.
Additional:
* E.M.P. is a large mana burn nuke which can hit Medusa's Mana shield with enough damage to lose even more mana.
* Deafening Blast disarms Medusa's ability to deal pseudo-AOE damage during teamfights.
* Cold Snap allows the opposing team to repeatedly stun Medusa in short succession, preventing her from successfully casting her ultimate due to its long cast time.
Invoker
*
Nether Ward on its own can greatly hinder Invoker from casting many of his abilities, at least until he gets a significant amount of HP or is under the protection of spell immunity from 
Black King Bar
Life Drain provides True sight, revealing Invoker through Ghost Walk, and forcing him or his allies to use an ability or item to interrupt its channeling
Decrepify when it is used defensively, Tornado or Cold Snap to prevent Pugna from channeling 
Life Drain
Decrepify on Pugna's allies means Invoker's abilities can be used to deal more damage to them.
*
* Outside of Nether Ward's range, Invoker shall have the advantage, as Invoker has Tornado to purge Pugna's
* A poorly used
Additional:
* Because Invoker relies on casting a large amount of spells to contribute to fights, Nether Ward can force him to not cast anything at all or take a large amount of damage to cast spells.
Legion Commander
*
Decrepify on either hero stops Legion Commander from completing a Duel, and dissuades her from initiating Duels on ethereal allies.
Life Drain can help Pugna's teammates win a fight, either by killing Legion Commander or replenishing her target's health.
Duel, regardless if it's used on her or on the ally .
*
Additional:
* Decrepify prevents Legion Commander from attacking allies during
* Pugna can easily cast Decrepify, Nether Blast and Life Drain on Legion during the 4/4.75/5.5/8 seconds of duel