Former two-weight world champion Conor McGregor was left stunned on his return to the UFC as Dustin Poirier claimed victory in their rematch at UFC 257.
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.
"I have no excuses. It was a phenomenal performance by Dustin. I have to dust it off and come back. I need activity, you don't get away with being inactive in this business." said McGregor.
