Irish boxer Conor McGregor was defeated for the second time in two fights after breaking his leg at UFC 264 on Saturday night in Las Vegas.
The 32-year-old 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 sat on the canvas with his ankle strapped in a protective cast, before being taken out of the ring on a stretcher.
UFC president Dana White said after the fight that McGregor had broken “the lower tibia in his left shin”.
McGregor had defeated Poirier via first-round TKO at UFC 178 in 2014, but the American, also 32, evened the score with a second-round TKO at UFC 257 in January.
It meant the rivalry was perfectly poised heading into their trilogy bout in Las Vegas, and it was Poirier who emerged victorious in unfortunate circumstances.
The action started fast and furious as McGregor switched his tactics from the second fight and opened up with a succession of kicks.
But Poirier, 32, kept his cool and, after fending off McGregor’s early attacks, pushed forward with a flurry of punches before eventually forcing the action against the cage.
McGregor attempted to surprise Poirier with a guillotine choke, but the American stayed calm and escaped before punishing McGregor with heavy punches and elbows from top position.
And, when the fight returned to the feet, both men attempted to throw huge shots, with McGregor rolling his ankle when stumbling backward. Poirier then poured on the pressure in search of a finish, but the Irishman was saved by the buzzer.
However, it quickly became apparent that McGregor had suffered a serious injury, with replays showing the Irishman’s leg breaking as he stepped backward.