Former two-weight world champion Conor McGregor was left stunned on his UFC return as underdog Dustin Poirier claimed victory via a TKO in their rematch at UFC 257.

McGregor came out of retirement for a third time to face fellow 32-year-old American Poirier at Abu Dhabi’s Fight Island.

And although the Irishman edged the first round, Poirier unleashed a flurry of punches to seal a technical knockout two minutes 32 seconds into round two.

“I’m gutted, it’s a tough one to swallow,” said McGregor.

“I felt stronger than him, but his leg kicks were good. I didn’t adjust. My leg was badly compromised, I’ve never experienced those low calf kicks, and I wasn’t as comfortable as I needed to be.

“I have no excuses. It was a phenomenal performance by Dustin. I have to dust it off and come back.”

McGregor was catapulted into global stardom when he beat Poirier in the octagon in their first clash – a featherweight bout in September 2014 – stopping the American inside 106 seconds.

The win made him UFC’s first simultaneous two-weight champion before facing Floyd Mayweather in one of the richest bouts in boxing history in 2017.

Poirier had to gradually work his way back into title contention and is now the interim lightweight champion, losing just two of his 13 fights since.

McGregor now has a 22-5 mixed martial arts record having lost three of his past six UFC fights.

McGregor has been relatively inactive though. Since losing to Khabib Nurmagomedov in 2018, he has had just 40 seconds in the octagon – beating Donald ‘Cowboy’ Cerrone in style last January.

But McGregor seemed to start well in front of about 2,000 fans at the new 18,000-capacity Etihad Arena. He survived an early takedown and pinned Poirier against the fence for most of the first round, landing a few shoulder strikes like those that did so much damage against Cerrone.

But, unlike their first fight, Poirier was unmoved, replying with a series of leg kicks.

And it was the American southpaw that brought the heat midway through the second round, pouncing on McGregor to take his record to 27-6.

“It was a lot of things, but it wasn’t payback. That wasn’t the driving force,” said Poirier.

“The first time I was a deer in the headlights. This time he was just another fighter that bleeds just like me.

“The goal was to be technical, pick my shots and not brawl at all. Then I had him hurt so I went a little crazy.”