* Both Guardian Angel and Purification are perfect counters against Duel.
Additional:
* 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.

* Heavenly Grace reduces Fireblast stun time and dispels Ignite.
* Purification can heal damaged hero if needed.

* 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.

* Ogre Magi has single-targeted magical-only damage and disables and is less effective against Meepo's clones.

* 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.

* In general, heroes that deal burst in multiple instances will trigger Borrowed Time and heal Abaddon for a large amount, such as Skywrath Mage, Techies, Juggernaut, Shadow Shaman, or Ogre Magi.

* Winter Wyvern's Winter's Curse works very well against the increased attack speed from Bloodlust.

* 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.

* Fate's Edict gives full immunity from Ogre Magi's mostly magical damage.
* Fortune's End can dispel Ignite (when used on allies) and Bloodlust (when used on enemies).
* False Promise can dispel Ignite and Fireblast.

* 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.

* Atrophy Aura's percentage-based damage reduction greatly diminishes Legion Commander's overall damage output, even if she has won many Duels.
* Dark Rift can be used to save Underlord or his allies from Duels if properly timed.
Additional:
* Atrophy Aura makes it hard for Legion Commander to win Duels.
* Dark Rift can be used to save Underlord and his allies from a Duel.

* 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 on.
* 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.

* Undying saps strength from heroes with Decay, and Ogre Magi's high strength gain will allow Undying to steal more and more strength, becoming stronger with each use.
* Due to the Strength steal from Decay, Undying is normally very tanky, and has high health, making it harder for Ogre Magi to kill him.

* 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.

* Wave of Terror can reduce Legion Commander's survivability during a Duel.
* Magic Missile and Nether Swap disrupts Duels and saves allies.

* Arc Warden's Tempest Double is helpful for killing Ogre Magi who lacks AoE damage and disables.

* Magnetic Field prevents Legion Commander from easily gaining wins with Duel.
Additional:
* Magnetic Field prevents Legion Commander from getting wins with Duel.

* God's Strength with Sven's tankiness and item build makes him difficult to take down in Duels.
* Storm Hammer can be used to interrupt Duels (until Legion Commander buys Aghanim's Scepter).
* Sven also has a talent at level 15 that allows Storm Hammer to apply a basic dispel on any enemies hit by it, which can remove the buffs from Overwhelming Odds and Press the Attack.
* Warcry gives a shield to Sven's teammates, which can completely waste Duel's duration depending on how much strength Sven has.

* 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.

* 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.

* 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.
Additional:
* Decrepify prevents Legion Commander from attacking allies during Duel, regardless if it's used on her or on the ally .
* Pugna can easily cast Decrepify, Nether Blast and Life Drain on Legion during the 4/4.75/5.5/8 seconds of duel

* Nethertoxin breaks Multicast.
* Corrosive Skin minimizes the damage during Ignite and Fireblast.

* Provided Luna is able to cast it in time, Eclipse can help win a Duel from Legion Commander.
* If Luna isn't the target, she can easily use Lucent Beam and Eclipse to win the fight for the ally.
Additional:
* 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 players will always have a Black King Bar or Aghanim's Scepter handy since both abilities do not pierce through spell immunity.

* Mystic Flare can easily burst down Legion Commander while she is Dueling.

* 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.

* Ogre Magi has nothing against Rage and his high health pool amplifies Feast.
Additional:
* Lifestealer's Rage makes him immune to all of Ogre's magical debuffs and also dispels them.
* Ogre's as hero with great durability and high health is great target for Lifestealer in any stage of the game, thanks to Feast.

* Dragon Knight's high natural sustain and health regeneration from Dragon Blood makes him hard to take down in Duels.

* 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.

* 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.

* Doom makes Ogre Magi less disruptive.
* Infernal Blade effectively negates Ogre Magi's tankiness.
* With Aghanim's Scepter he can disable Multicast.

* Mana Shield makes Medusa very hard to take down in Duels.
* Stone Gaze stops Legion Commander from Dueling altogether, regardless of who she targets.

* Dark Pact dispels Ignite's slow and Fireblast's stun.
* Shadow Dance allows Slark to regenerate HP, even when he is affected by Ignite and Fireblast.

* 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

* Clinkz, Sniper, Lone Druid, Troll Warlord, Legion Commander, Wraith King and others are some of the Heroes that bases themselves on attacks with little or no spell power, suffering in the grassy hands of Overgrowth.

Additional:
* Living Armor's global range makes it nearly impossible for Legion Commander to win Duels in the early to mid-game.

* 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

* Heroes who can hide the Dueled target (Outworld Devourer, 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.

* Troll Warlord's melee bash and high attack speed can often help him and his allies win Duels against 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

* 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.

* Puck silences Ogre Magi with Waning Rift, and Phase Shift makes Puck untargetable for the duration.

* Legion Commander is unlikely to win a Duel against Ursa.

Additional:
* 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.
* Fury Swipes can give Ursa the edge in Duels.

* Heroes who can hide the Dueled target (Outworld Devourer, Shadow Demon, Tusk, Phoenix with Aghanim's Scepter etc).

Additional:
* Outworld Devourer 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.

* Phantasm dispels Ignite and makes targeting the real Chaos Knight much harder.

* Enfeeble, Nightmare and Fiend's Grip all prevent Legion Commander from winning Duels, especially when Bane has Blink Dagger.
Additional:
* 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.

* Song of the Siren lasts long enough to prevent a successful Duel (but only if Naga wasn't the target).