Dustin Poirier

Dustin Poirier beats Conor McGregor after Irishman breaks leg in the first round at UFC 264

The Irishman, 32, was stopped after the first round against former interim lightweight champion Dustin Poirier.

Replays showed his ankle rolling over as he stepped backwards seconds before the end of the round and the fight was stopped by doctors, handing Poirier a second straight win in their trilogy.

"This is not over," McGregor said.

"If I have to take it outside, let's take it outside," he added as he was interviewed while sitting on the canvas with his ankle strapped in a protective cast, before being taken out of the ring on a stretcher.

McGregor v Poirier 2: Irishman shocked in UFC rematch at Fight Island

McGregor came out of retirement for a third time to face fellow 32-year-old 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.