LONDON (AFP) - Dillian Whyte's hopes of a world heavyweight title fight suffered a major setback when former Olympic champion Alexander Povetkin twice came back off the canvas to knock out the British fighter.

Whyte, 32, had been the World Boxing Council's No. 1 contender for over two years and was hoping victory behind closed doors on Saturday (Aug 22) would pave the way for a world title shot at either defending champion Tyson Fury or Deontay Wilder.

Whyte twice put Russian 40-year-old Povetkin down in the fourth round but was then knocked out in fifth by the former World Boxing Association world champion.

"I didn't feel I would finish the fight like this. I was confident in the fourth round even after going down twice," Povetkin told Sky Sports after winning the bout courtesy of a devastating left hook.

Promoter Eddie Hearn added: "When the punch landed, I thought it was a dream. I can't believe it.

"Two heavy knockdowns from Whyte - people felt it was over. This is the drama of heavyweight boxing. One punch completely changed the fight.

"It is a shock. He wasn't that much of an outsider - we knew how good Povetkin was. It was a thrilling knockout on a thrilling night."