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 knock-out. Whyte had dominated the opening four rounds and twice sent the 40-year-old Russian to the canvas. But Povetkin 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. There was a sedate start to the fight as Whyte began to establish his impressive jab and Povetkin struggled to make an impression. Povetkin was left off balance by a strong right in the third and Whyte troubled the Russian further as he worked well to the body. Whyte was getting more confident by the round and Povetkin took a count after being dropped to the floor by a right-left combination early in the fourth. Povetkin was looking out of his depth and he was sent tumbling to the canvas again by a short left uppercut close to the bell. It looked as if the end was near for the Russian but he landed a perfect punch from nowhere that left Whyte on the floor for some moments, although he was able to eventually get to his feet. “I didn’t feel I would finish the fight like this but I was pretty confident in the fourth round,” Povetkin told Sky Sports. “I went down twice but it was OK. It was not too much damage. I was watching his fights and I see that he was missing uppercuts from the left and from the right. All my training I trained for those shots and it was definitely one of the best punches of my career.” The promoter Eddie Hearn, who confirmed there was a rematch clause which he will exercise before the end of the year, said: “I can’t quite believe it to be honest. When the punch landed I felt I was in some dream. The fight was over virtually after two heavy knockdowns, but this is the drama of the sport we love. This is the drama of heavyweight boxing and one punch can change everything.” Meanwhile, Katie Taylor retained her lightweight world titles with a unanimous points decision over Delfine Persoon. Taylor was pushed to the limit for the second time by Persoon at Matchroom HQ in Essex, but the judges’ scorecards were 98-93, 96-94, 96-94 in her favour. Taylor won a contentious points decision at Madison Square Garden on a night when many observers felt Persoon had done enough to get the verdict. The Irish fighter started well in Saturday’s second encounter and pushed Persoon back with a couple of strong left hooks. Persoon was heavily marked under the right eye in the second round as Taylor continued to dominate. But the Belgian’s high workrate began to trouble Taylor and the Irish champion also sustained a nasty swelling on her forehead. Persoon refused to take a backward step and she landed a high volume of shots, with her right hand proving highly effective. Taylor responded with a burst of punches on the bell as Persoon tumbled to the floor almost in exhaustion. Person, who said after the fight she might have broken her nose in the second round, was gracious in defeat and felt Taylor had done enough to retain her WBC, IBF, WBO and WBA titles.