Former WWE superstar CM Punk suffered defeat on his UFC debut, submitting to Mickey Gall inside the first round of their welterweight clash in Cleveland.
The 37-year-old, who left the WWE in 2014 after a nine-year association with the company to pursue a career in the UFC, was under pressure from the first bell and was on his back less than 10 seconds into the fight.
Gall had promised to "destroy" Punk in the build-up to the fight and was quickly in control, shooting with a double-legged takedown.
Punk, pinned up against the fencing, was unable to wriggle free from under Gall and was caught by numerous blows to the head, including a powerful right to the temple.
In his attempts to get free, Punk was then locked into a rear-naked choke by Gall and left with no option but to tap his hand on the mat just 2.14 into the first round.
"Yeah you know in life you go big or you go home," Punk said. "I just like to take challenges. It was a hell of a climb, I didn't get to the summit tonight but it doesn't mean I'm going to give up it doesn't mean I'm going anywhere, it doesn't mean I'm going to stop."
"Obviously, Mickey's a hell of a fighter. I will be back, believe it or not. This was the most fun I've had in my life, second best night of my life after marrying my wife.
"I know there's a lot of doubters but listen, life's about falling down and getting back up. Doesn't matter how many time you get knocked down, get back up."
Meanwhile, Stipe Miocic retained his UFC heavyweight title with a first-round knockout victory over Alistair Overeem.
However, Miocic did not have it all his own way and was floored by a short left early in the bout before being placed in a guillotine hold as Overeem attempted to choke him out.
The heavyweight champion managed to escape the hold and quickly asserted his dominance on the fight, stunning Overeem with powerful punch before delivering four devastating right-hand punches to clinch victory with 33 seconds left in the round.
"He hit harder than I thought, he knocked me down but I wasn't hurt," Miocic said.
"I said I would keep this belt for a long time and I did it. I wanted to shut him down, turn the mother board off."