* Bristleback's tankiness and damage reduction from the rear makes him very hard for Phantom Lancer to chase and finish off, due to his lack of burst damage.
* Quill Spray destroys Phantom Lancer's illusions.
* Bristleback's passive costs no mana, meaning that it will continue to trigger even if Phantom Lancer drains Bristleback's mana with Diffusal Blade.
Additional:
* Quill Spray cleans up Phantom Lancer's illusions in no time.
* Phantom Lancer's complete lack of burst damage makes it nearly impossible for him to kill Bristleback during chases.

* Phoenix's AoE abilities can prove troublesome for Phantom Lancer.
* Fire Spirits dramatically reduces Phantom Lancer and his illusions' attack speed.
* Icarus Dive's movement speed reduction makes retreating difficult.
* Supernova burns away illusions, and is invulnerable to attacks from illusions.

* Lone Druid and The Spirit Bear cannot burst down Bristleback due to Bristleback
* Bristleback can easily run to Lone Druid without any hesitation, with Viscous Nasal Goo to reduce armor and slow the Spirit Bear or Lone Druid and Quill Spray can deal damage to both Lone Druid and the Spirit Bear at the same time

* Lone druid's bear attacks on Phoenix's Supernova Egg don't increase the hit count. Given that Lone Druid's main hero often doesn't have much farm, the Supernova Egg is less likely to get killed.

* Sand King has nothing to deal with Supernova, as none of his spells are effective.
* The damage-over-time abilities of Phoenix disable Sand King's Blink Dagger very often.

* Quill Spray will hit Sand King inside Sand Storm, damaging him and putting Sand King's Blink Dagger on cooldown, preventing him from escaping.
* Epicenter's numerous damage ticks will trigger Bristleback's passive repeatedly during teamfights.

* Bristleback decreases Tiny's high burst damage against Bristleback.
* Tiny's high damage will also proc Bristleback multiple times.
* Viscous Nasal Goo can help counteract the bonus armor granted by Grow.

* Heroes that are able to slow Tiny's attack speed, like Tusk and Phoenix, will greatly limit his Physical damage output.

* Bristleback is one of the hardest heroes to gank with a Meat Hook and Dismember combo, and attempts to do so sometimes backfire on Pudge.
Additional:
* Pudge is particularly susceptible to Bristleback's Viscous Nasal Goo and Quill Spray due to his naturally low armor & poor agility gain.
* Bristleback, in combination with his strength gain, high health, common itemization for magic resistance and damage reduction from Bristleback makes him a poor target for Pudge.

* Heroes with high health especially Strength heroes will take more damage on Sun Ray: Axe, Pudge, Bristleback, Mars.

* Illusion-based heroes such as Naga Siren or Chaos Knight are vulnerable to Phoenix's DPS and attack speed slow, as their illusions, no matter how many, will be unable to deal enough damage to actually be a threat, and they will all be completely useless against the Supernova.

* Quill Spray quickly destroys Chaos Knight's Phantasms.

* Heroes who continue dealing damage while being stunned: Luna, Razor, Axe, Bristleback, Leshrac,

* Due to Spirit Breaker's low attack speed, Supernova is problematic for Spirit Breaker to take down, and even more so with Fire Spirits debuff applied.
* Icarus Dive grants Phoenix capability to quickly escape to safety.

* Heroes with slow movement speeds and small health pools (supports like Crystal Maiden or Witch Doctor) are easy targets for Phoenix. Should they be inflicted by its DOT debuffs, they will be very quickly killed without even getting a chance to fight back.

* Viscous Nasal Goo can hinder Crystal Maiden's already abysmal mobility, which allows Bristleback (or his teammates) to run her down and kill her.
* Bristleback frequently builds Blade Mail, which can quickly kill Crystal Maiden if her ultimate is used while he is under its effect.
* The passive part of Bristleback will trigger many, many times under the damage from Freezing Field, and as the stacks increase, the damage output from each successive cast (or proc) will eat away at Crystal Maiden's small HP pool.

* Supernova negates Kunkka's combo entirely, as it can't be affected by spells while using Supernova.
* Icarus Dive also allows Phoenix to dodge Ghostship and Torrent.

* Viscous Nasal Goo slows down Dragon Knight and lowers armor, locking him down and making him more vulnerable.

* Phoenix's large damage over time with Icarus Dive and Fire Spirits can kill Chen's allies before he can use Hand of God.
* Phoenix's Supernova is not damaged by Chen's creeps.
Additional:
* Not only Phoenix is able to disrupt Chen's jungling with Fire Spirits, but its high damage over time can also force Chen to use Hand of God prematurely, potentially wasting any chance to save his allies during teamfights.
* Creeps' damage and attack speed are very abysmal, so Chen often cannot kill Phoenix whenever it casts Supernova.

* Bristleback's abilities are nearly useless for Rubick to Spell Steal, as he does not gain the bonuses from Warpath.
Additional:
* Rubick deals little damage on his own, so Bristleback can simply shrug off all his spells and chase you down with his spells and attacks.
* Quill Spray requires multiple casts and close range to add up stacks. Because Rubick does not stay in the front lines, it's generally not a good spell for him to steal.
* Viscous Nasal Goo will slow Rubick down even further and reduce his armor, making him vulnerable to Quill Spray and the damage bonus from Warpath.

* While her Phantom Strike does give limited extra attack speed, she cannot use the ability against the Phoenix Sun, and while her Blur may protect her from attacks, Phoenix's strong magical DPS burns away her small health pool quickly, and the attack speed slow makes her unable to fight back (provided she has no source of spell immunity).
Additional:
* Fire Spirits applies a severe attack speed slow, severely hindering Phantom Assassin's damage output. While Phantom Strike may be able to slightly remedy the problem, Phoenix' magical and pure damage output completely ignore Blur's evasion, resulting in severe damage to her low health pool.

* Phoenix will usually be on the sidelines or further back ready to use Sun Ray. Even after Magnus successfully uses Reverse Polarity and skewer Phoenix's teammates, Phoenix can usually counter-initiate using all of its abilities.

* Icarus Dive allows Phoenix to shrug off the slow from her trap and make an easy escape from her ambush.
* As Templar Assassin relies on her quality-over-quantity bursting attacks to make quick work on fragile target, Fire Spirits' attack speed reduction can cripple her ability to deals any damage during combat. With the debuff applied in early-mid game, a Meld-breaking hit from her is significantly slowed to the point that her target can make a safe distance before she even landed the hit.
* Sun Ray has quick damage tick and will burn through her Refraction in no time.
* Supernova deals damage over time in an incredibly large area, and again with her quality-over-quantity style, she may not be able to attack quickly enough to break through the Phoenix Sun by herself. (not to mention the debuff from Fire Spirits) This can lead to a failed ganking attempt or even a turnaround.
Additional:
* Her Refraction charges can and will be easily burned away by Phoenix's damage over time abilities, and Meld can't protect her from Phoenix's AoE abilities, even without detection.

* Supernova allows Phoenix to save himself (or an ally, with Aghanim's Scepter) through Echo Slam. Earthshaker will also have a difficult time destroying the supernova, due to his low base attack time and poor agility.
* Icarus Dive can pass through Earthshaker's Fissure.
* Most of Phoenix's abilities disable Earthshaker's Blink Dagger for a good period of time due to the damage-over-time nature of its spells.

* Macropyre's frequent damage ticks causes Bristleback to activate repeatedly, resulting in free damage as long as Bristleback faces away from Jakiro.

* Quill Spray and Bristleback harass Luna more efficiently than she does with Lucent Beam.
* Bristleback withstands Luna’s nukes, and gives lots of damage in return.
* Viscous Nasal Goo and Warpath are enough to outrun a speedy Luna.
* Bristleback tends to be a frequent carrier of Crimson Guard, which is good protection from bouncing glaives.
Additional:
* Multiple instances of damage from Eclipse will trigger Bristleback's passive repeatedly in a short time, dealing tremendous damage to Luna and her teammates.
* Luna's damage burst may be high, but it will not be enough for her to take down Bristleback.

* Lycan's wolves deal little damage to Bristleback, and are easily killed by Quill Spray, even when they're invisible.
* Lycan's lack of burst damage makes it very hard for him to kill Bristleback, especially when his back is turned.
Additional:
* Quill Spray can be used to kill Lycan's summons.
* Bristleback allows him to stay alive against Lycan while dishing out counter attacks
* He can overpower Lycan with his Warpath instead.

* Phoenix's Supernova cannot be damaged by Familiars.
* In the early and mid game, Sun Ray won't deal enough damage to be reduced by Gravekeeper's Cloak.
* Once Sun Ray deals enough damage to protect Visage, a layer of Gravekeeper's Cloak is burnt every 0.2 seconds.

* Quill Spray's constant AoE damage will hit Dark Willow even in Shadow Realm. Its automatic damage will hurt her if she tries to get close and use Bedlam.

* Bristleback's tankiness can enable him to chase Enigma out of a teamfight, making it difficult to initiate with a Black Hole.

* Clockwerk being confined in his own Power Cogs means Clockwerk is unable to quickly escape from Phoenix's Sun Ray and Supernova.
* Sun Ray will also heal the enemy Clockwerk is fighting, making it unlikely for Clockwerk to take an enemy down with him.
* For the same reasons, Phoenix also makes a powerful ally for Clockwerk when the situation is reversed.

* The bonus Backstab damage from Cloak and Dagger is rendered irrelevant with Bristleback and hurts Riki more than him because of the passive Quill Spray.
* Riki still gets damaged by Bristleback's Quill Spray while invisible, and it can be hard to deal with in lane.
* Bristleback is not too bothered by Smoke Screen. Though he cannot use Quill Spray manually inside it, it still procs passively when he takes damage from the back. The movement speed from Warpath allows him to get out of the area easily.
* Due to Bristleback's natural tankiness, he is an ideal Gem of True Sight carrier.
* Riki rarely buys Silver Edge to break Bristleback's passive because the invisibility aspect of it is redundant.
Additional:
* Quill Spray will hit Riki even when he is invisible.
* Cloak and Dagger's bonus backstab damage is rendered irrelevant against Bristleback.
* Smoke Screen does not stop Bristleback's passive from activating.
* Due to Bristleback's natural tankiness, he is an ideal Gem of True Sight carrier, directly countering Riki's invisibility.

* Quill Spray destroys spiderlings, and hits Broodmother even when she's regenerating in her webs. This makes Bristleback one of her hardest counters in lane.
Additional:
* Bristleback reduces most of Broodmother's and her spiderlings' damage.
* Quill Spray will hit any spiders in its proximity, hindering Broodmother's fighting and farming capabilities.

* Heroes that have AoE damage: Lina, Keeper of the Light, Timbersaw, Leshrac, Bristleback, Axe

* Heroes with wide AoE abilities will reveal Monkey King through Mischief: Necrophos, Phoenix, Alchemist, Earthshaker, Razor, Tinker, Leshrac, Queen of Pain

Additional:
* Icarus Dive, Sun Ray, and Supernova all destroy trees that Monkey King relies on to use his ability Tree Dance. If you spot him, you can quickly Icarus Dive in his direction and then follow up with Fire Spirits and Supernova. If you manage to cut the tree he is on, he will be stunned for 4 seconds and will be forced to take a lot of damage. However, most Monkey King players tend to build attack speed items to make use of their passive, Jingu Mastery, so a battle against a farmed Monkey King will depend on who gets the jump on the other first.

* Other heroes who has armor and slow debuffs won't allow Medusa to disengage from combat: Tidehunter, Bristleback, Slardar.

* Heroes with slow movement speeds and small health pools (supports like Crystal Maiden or Witch Doctor) are easy targets for Phoenix. Should they be inflicted by its DOT debuffs, they will be very quickly killed without even getting a chance to fight back.

* Heroes who depend on attacks (such as Shadow Fiend or Drow Ranger) can be nullified by Fire Spirits' attack speed slow.

* Sand King and Phoenix has many tools to deal with a crowd of Heroes, which will work well against a crowd of illusions.

* Phoenix with Supernova
* Heroes that can dodge Glimpse:
* Puck with Phase Shift
* Riki with Tricks of the Trade
* Phantom Lancer with Doppelganger
* Ember Spirit with Sleight of Fist and Activate Fire Remnant
* Chaos Knight with Phantasm
* Naga Siren with Mirror Image
* Tusk with Snowball
* Juggernaut with Omnislash
* Brewmaster with Primal Split
* Lifestealer with Infest
* Phoenix with Supernova

* Heroes who can slow and kite Axe will severely inhibit his presence in fights: Bristleback, Crystal Maiden, Batrider, Arc Warden, Winter Wyvern, Clockwerk

* Heroes with high health especially Strength heroes will take more damage on Sun Ray: Axe, Pudge, Bristleback, Mars.

Additional:
* Sun Ray allows Phoenix to heal any allies caught in Berserker's Call, while burning away Axe's high HP at the same time.
* Axe's slow attack speed makes it difficult for him to destroy Supernova on his own.

* Bristleback's Viscous Nasal Goo can catch and slow Bounty Hunter. Warpath and Quill Spray can defeat him quickly due to his small HP pool when compared to Bristleback's.

* Heroes with damage-over-time abilities will not only proc Bristleback's passive continuously, they will also do little harm to him when he is facing away from the source: Venomancer, Arc Warden

* Heroes who depend on attacks (such as Shadow Fiend or Drow Ranger) can be nullified by Fire Spirits' attack speed slow.

* Icarus Dive quickly escapes from Shadow Demon abilities, especially Demonic Purge.
* Phoenix AoE abilities remove Shadow Demon's illusions created by Disruption.

* Quill Spray is very effective against Io, as it has very low armor and has to stay close to the fight to not break its Tether.

* Icarus Dive helps Phoenix escape the slow from Stroke of Fate's and Soulbind.
* Supernova protects Phoenix from spell damage during Soulbind.

* Heroes with high physical damage can damage Lifestealer more than he can heal: Bristleback, Clinkz, Luna,Shadow Fiend, Slardar

* Quill Spray usually hits Meepo's clones, although Bristleback cannot turn his back when rooted with Earthbind.

* Bristleback's tankiness and Bristleback allow him to outlast Burning Spears' damage-over-time at almost any point in the game. In addition, if Huskar chooses to cast Life Break on Bristleback, Bristleback can simply turn around before it hits and receive little damage.
* Viscous Nasal Goo will reduce Huskar's low armor even further, and Quill Spray and Warpath will tear him down extremely quickly.
Additional:
* The damage from Burning Spear can be reduced by turning away from Huskar.
* Bristleback can bait Huskar into using Life Break on him, then turn around and receive very little damage.

* Fire Spirits does damage over time, preventing Faceless Void from backtracking the full damage with Time Walk.
* Fire Spirits applies a big attack speed slow, stopping Faceless Void from doing many attacks while in Chronosphere.
* Sun Ray can heal allies and damage Faceless Void from outside Chronosphere.
* Supernova can be cast outside of Chronosphere, forcing Faceless Void to step away from it, lest he'll take a lot of damage

* Fortune's End cannot dispel Warpath stacks on Bristleback or Quill Spray stacks on allies.
* Bristleback can heavily reduce Oracle's damage output. With it, Oracle may accidentally heal Bristleback with Purifying Flames, especially if Bristleback has bonus magic resistance.

* Heroes with hiding abilities can protect disabled allies: Outworld Devourer, Shadow Demon, Tusk, Phoenix with Aghanim's Scepter

* Bristleback need not worry about charging into Magnetic Field, and quickly clearing up Arc Warden's summons and Tempest Double with Quill Spray.
Additional:
* Bristleback activates frequently while he escapes from Arc Warden's Necronomicon army.
* Arc Warden has little armor and mobility, which makes him an easy target to apply Quill Spray and Viscous Nasal Goo stacks.