Conor McGregor's much-hyped return to the octagon lasted just over a minute after the Irishman blew out his knee and retired injured in his UFC 329 fight with Max Holloway in Las Vegas.
Former two-weight world champion McGregor, who had not fought since breaking his leg against Dustin Poirier in July 2021, attempted a flying kick to start the opening round on Saturday night (Sunday AEST), but landed awkwardly and immediately looked in trouble.
He tried to fight on for a few seconds but looked towards the referee to signal he could not continue.
Former featherweight champ Holloway said he would discuss the possibility of staging another fight with McGregor when the Irishman recovers.
"It is what it is, I'm going to sit down with the UFC," Holloway said.
"(There was) so much hype for that right there. We've got to run it back one more time. One more time for the boys."
Saturday's bout was the second between the pair, with McGregor winning by unanimous decision in 2013.
"My head gasket is gone. Destroyed," McGregor said on social media.
"I had no injury / injuries going into the fight. I was throwing kicks, planted and jumping, all throughout camp as well as backstage before the fight. This came out of nowhere. I am beyond dark here. I can only describe it as hell."
Asked if there may have been an existing injury, UFC president Dana White said there were no signs of it at Friday's weigh-in.
"Five years off in this sport is rough," White said. "We're assuming a blown ACL. That's what I assumed when I saw it, and that's what the doctors think, too."
Injuries and issues away from the sport have derailed McGregor's career.
After breaking his leg against Poirier five years ago, the 37-year-old was slated to meet Michael Chandler in June 2024, but that was cancelled after McGregor suffered a broken toe in training.
Later that year a jury in an Irish civil court found him liable for the rape of Nikita Hand in 2018.
In October 2025, he accepted an 18-month ban for "whereabouts failures" after he missed three attempts by Combat Sports Anti-Doping to collect biological samples from him in 2024. The ban was backdated and expired in March.
In the co-main event at the T-Mobile Arena on Saturday, Britain's Paddy Pimblett also needed less than a minute to secure victory, choking out Frenchman Benoit Saint-Denis in their lightweight bout.
- with AP
Australian Associated Press
