Daniel Dubois retained the IBF heavyweight title by knocking out former two-time world champion Anthony Joshua in the fifth round in a dominant first defence of his belt on Saturday.

Joshua had already been floored in the first and third rounds of a surprisingly one-sided fight at Wembley Stadium before falling face first after a straight right hand by Dubois. The referee waved off the all-British fight just as Joshua's corner threw in the towel.

Dubois roared "Are you not entertained?" to a record post-war boxing crowd in Britain of 96,000 fans in his first words after the fight.

Joshua entered as the favorite as he sought to emulate boxing greats like Muhammad Ali and Lennox Lewis as a three-time heavyweight champion.

However, he was outclassed by Dubois, who completed his mission to legitimize his status as a heavyweight titleholder.

Dubois has put himself in position to potentially fight the winner of the rematch between WBA, WBC and WBO champion Oleksandr Usyk and Tyson Fury.

"I'm a gladiator. I'm a warrior to the bitter end," Dubois said. "I want to go to the top level of this game."

Possible rematch

Joshua vowed to continue boxing after a fourth defeat over the last five years, and his promoter, Eddie Hearn, said he wanted to exercise the rematch clause.

This was the worst of all those losses, though. Joshua was saved by the bell in the first and third rounds after the knockdowns.

"I had a sharp opponent, a fast opponent," Joshua said. "A lot of the mistakes were mine."

Dubois was positive from the start, dominating with his right hand, and was well in control by the time he knocked down Joshua the first time with an overhead right.

Joshua stuck out his tongue at Dubois as he walked back to his corner but he was clearly hurt as he returned for the second round.

After Dubois let his hands go, Joshua fell into the ropes after being hit by the left. His legs were wobbling as the referee did an eight-count but he survived.

Joshua appeared disorientated, swung wildly and fell to the canvas twice in the fourth round, though both were ruled as slips.

The end came 59 seconds into the fifth as Joshua attempted to get on top of Dubois. The champion rocked his opponent with a left hook and then caught him again with a right that sent Joshua down.

"Credit to him and his team, we came up short," Joshua said.