Dillian Whyte's world title dream was left in tatters as Alexander Povetkin inflicted a second career defeat on him with a sensational fifth round knockout.
Whyte had dominated the opening four rounds and twice sent the 40-year-old Russian to the canvas.
But Povetkin, who went down twice in the earlier round, turned the fight on its head with a ferocious left uppercut that ended the fight in an instant.
Whyte, the WBC’s number one contender for over two years, knew he could not afford any mistakes behind closed doors at Matchroom HQ in Essex.
The prize of meeting the winner of the trilogy fight between current champion Tyson Fury and Deontay Wilder was on the line.
Whyte's promoter, Eddie Hearn, was shocked by the outcome.
The win makes Povetkin the mandatory challenger to the WBC world title - and now puts him back in the mix for major fights after fighting to a draw in his last outing, with Michael Hunter in December.
"I can't quite believe it," Hearn said. "When the punch landed, I felt like I was in some dream.
"The fight was over, virtually, Povetkin hadn't started well, I thought Dillian Whyte was measuring up.
"He had a great finish to the round when he knocked Povetkin down. I felt that it was over, but this is the drama of the sport, this is the drama of heavyweight boxing. One punch can change everything."
