Conor McGregor is known worldwide for his knockout power, sharp left hand, and fearless mindset inside the octagon.
For years, fans associated his name with fast finishes and highlight-reel stoppages. He knocked out legends, dominated divisions, and built one of the biggest fan bases in combat sports history.
Conor McGregor has been submitted by a few fighters during his career, but when it comes to being knocked out or stopped by strikes, the list is very short.
In fact, only one fighter has managed to knock out Conor McGregor, and that fighter did it twice.
That fighter is Dustin Poirier, famously known as Dustin “The Diamond” Poirier.
The rivalry between Conor McGregor and Dustin Poirier is one of the most important trilogies in UFC history. Their three fights told a complete story of growth, revenge, dominance, and heartbreak.
More importantly, it cemented Dustin Poirier as the only man to stop Conor McGregor with strikes in the UFC.
This article breaks down all three fights in detail, explains how Dustin Poirier achieved what no other fighter could, and why this rivalry still matters today.
Conor McGregor’s Reputation as a Knockout Artist
Before discussing the Poirier rivalry, it is important to understand Conor McGregor’s image inside the UFC.
From the start of his UFC career, McGregor built his reputation on precision striking.
He finished most of his opponents by knockout or technical knockout, often in the first round. His timing, accuracy, and confidence made him extremely dangerous.
By the time he reached his peak, many fans believed Conor McGregor could not be knocked out cleanly. Even when he lost, it was usually by submission or decision rather than strikes.
That belief changed only after his fights with Dustin Poirier.
Dustin Poirier: The Fighter Who Changed the Story
Dustin Poirier is not known for flashy trash talk or loud behavior. Instead, he built his career on toughness, skill, and consistency.
Poirier started his UFC journey as a featherweight and later moved up to lightweight, where he became one of the most respected fighters in the division. His boxing, durability, leg kicks, and fight IQ improved year after year.
When Poirier first faced Conor McGregor, he was still developing. By the time they met again, he had evolved into a complete fighter, and that made all the difference.
First Fight: UFC 178 – McGregor vs Poirier (2014)
- Event: UFC 178
- Date: 27 September 2014
- Weight Class: Featherweight
- Result: Conor McGregor wins by KO (Round 1)
The first fight between Conor McGregor and Dustin Poirier took place early in both fighters’ UFC careers. At that time, McGregor was rising fast, and Poirier was already an established name at featherweight.
From the opening seconds, the fight was intense. Dustin Poirier came forward aggressively, throwing combinations and trying to pressure McGregor. However, that approach played directly into Conor’s strengths.
McGregor stayed calm, used his footwork, and waited for the right moment. In the second minute of the first round, Conor landed a clean left hand that stunned Poirier. A few follow-up strikes ended the fight quickly.
This knockout victory made Conor McGregor a major star and pushed him closer to a title shot. At the same time, it left Dustin Poirier with a lesson that would shape his future.
The Long Gap Between Fights: Two Fighters, Two Paths
After UFC 178, both fighters went in very different directions.
Conor McGregor’s Rise
Conor went on an incredible run:
- Won the featherweight title
- Knocked out José Aldo in 13 seconds
- Became the first UFC fighter to hold two belts at the same time
- Became the biggest draw in UFC history
Dustin Poirier’s Growth
Dustin Poirier made important changes:
- Moved up to lightweight
- Improved his boxing defense
- Added powerful leg kicks
- Fought top contenders consistently
By the time they were matched again, Dustin Poirier was no longer the same fighter Conor had knocked out in 2014.
Second Fight: UFC 257 – Poirier’s First Knockout of McGregor (2021)
- Event: UFC 257
- Date: 24 January 2021
- Weight Class: Lightweight
- Result: Dustin Poirier wins by TKO (Round 2)
The rematch at UFC 257 was one of the most anticipated fights of the year. Fans were divided—some believed Conor would knock Poirier out again, while others believed Poirier’s growth would make the difference.
In the first round, Conor McGregor looked sharp. He landed clean punches and controlled much of the action. However, Dustin Poirier made a smart adjustment, leg kicks.
Poirier repeatedly attacked Conor’s lead leg. These kicks slowed McGregor down and reduced his movement. By the second round, Conor’s balance and speed were clearly affected.
Then came the turning point.
Dustin Poirier began landing heavy punches, pushing Conor backward. McGregor tried to defend, but Poirier’s pressure was relentless. A series of clean shots dropped Conor McGregor, and the referee stopped the fight.
This moment shocked the MMA world.
Dustin Poirier became the first fighter to knock out Conor McGregor in the UFC.
Why UFC 257 Changed Everything
The UFC 257 knockout was more than just a win for Poirier.
- It proved Conor McGregor could be stopped by strikes
- It showed Dustin Poirier’s technical growth
- It shifted the power balance in the lightweight division
From that night onward, Poirier was no longer just a contender, he was Conor McGregor’s biggest problem.
Third Fight: UFC 264 – The Shocking End (2021)
- Event: UFC 264
- Date: 10 July 2021
- Weight Class: Lightweight
- Result: Dustin Poirier wins by TKO (Doctor Stoppage – Round 1)
The third fight between Conor McGregor and Dustin Poirier received massive attention. The buildup was intense, emotional, and controversial.
Conor crossed several lines during trash talk, including comments about Dustin Poirier’s wife and family. This made the rivalry deeply personal and increased fan interest worldwide.
When the fight started, the pace was fast and aggressive. Both fighters exchanged strikes, and Poirier once again found success with leg kicks.
Near the end of the first round, Conor McGregor threw a kick that resulted in a serious leg injury. His leg broke as he stepped back, and he fell to the canvas.
The fight was stopped by the doctor between rounds.
Although it was officially ruled a TKO (doctor stoppage), the result still counted as another stoppage loss for Conor McGregor against Dustin Poirier.
This meant one clear fact:
Dustin Poirier had now stopped Conor McGregor twice by TKO.
Dustin Poirier’s Unique Place in UFC History
To this day, Dustin Poirier remains:
- The only fighter to knock out Conor McGregor
- The only fighter to stop him twice by strikes
- The winner of their UFC rivalry (2–1)
Many elite fighters have faced Conor McGregor, but none achieved what Poirier did.
Why Dustin Poirier Succeeded Where Others Failed
Several factors explain Poirier’s success:
- Improved Boxing Defense – He avoided early chaos and stayed patient
- Leg Kick Strategy – This weakened McGregor’s movement
- Durability – He survived early pressure
- Experience at Lightweight – Poirier was fully adapted to the division
These elements combined to create a perfect formula against McGregor.
Legacy of the McGregor vs Poirier Trilogy
The rivalry between Conor McGregor and Dustin Poirier will always be remembered as one of the most important trilogies in UFC history.
- It showed how fighters evolve
- It proved that preparation and discipline matter
- It produced unforgettable moments
For Conor McGregor, it was a reminder that no fighter is unbeatable.
For Dustin Poirier, it was proof that persistence and growth can change everything.
Final Thoughts
Conor McGregor’s career is filled with knockouts, titles, and global fame. But when it comes to being knocked out or stopped by strikes, only one man stands above the rest.
That man is Dustin “The Diamond” Poirier.
He knocked out Conor McGregor at UFC 257 and stopped him again at UFC 264, earning a unique place in UFC history.
No matter how the future unfolds, one fact will never change:
Dustin Poirier is the only fighter who knocked out Conor McGregor twice.