LONDON — Daniel Dubois has thrown Anthony Joshua’s career into disarray after knocking out his English rival with a right to the jaw in the fifth round as he made his first defence of his IBF heavyweight world title on Saturday.

Joshua (28-4, 25 KOs) endured a nightmare as Dubois (22-2, 21 KOs) knocked him down four times in rounds 1, 3 and 4 before brutally ending the bout 59 seconds into round 5.

Despite being the champion, Dubois pulled off a surprise victory by inflicting Joshua’s fourth professional defeat. Joshua had failed to retain the title of three-time world heavyweight champion. This happened in front of 96,000 fans at Wembley Stadium, the largest post-war stadium for a boxing match in the United Kingdom.

Much was made of Joshua’s knockout form, and he entered the fight following a brutal stoppage of Francis Ngannou in March. But it was Dubois’ power and aggression that decided the outcome as he hammered Joshua around the ring with ease.

The win sets up the possibility of Dubois challenging for the undisputed world heavyweight title in 2025, when he will fight the winner of the Dec. 21 bout between WBC, WBA and WBO champions Oleksandr Usyk and Tyson Fury, both of whom were ringside.

Usyk stopped Dubois in round 9 last August. Joshua must now hope for a rematch with Dubois, or perhaps a clash against the loser on December 21 after another serious setback in his career.

“I’m fighting to get all the glory, I’m the hunter and I have to hunt,” Dubois said.

Who does he want now?

“Good luck, maybe Usyk, a big contender for my redemption, but anyone can get it,” Dubois said.

“It’s been a journey and I’m grateful to be in this position. I’m a gladiator, I’m a warrior to the bitter end. I want to reach the top of this sport and reach my full potential.”

It was such a crushing defeat for Joshua that his options are being called into question and his reputation is indelibly damaged. There was talk of Joshua versus Fury before the fight, but this beating changes things after the 34-year-old bounced off the canvas and became confused in round 5.

“Before I came here, I always told myself I’m a fighter for life,” Joshua said afterwards. “Keep rolling the dice. I had a fast and sharp opponent, a lot of mistakes on my part.”

Dubois, who lives in Essex, revived his career with injury wins over Jarrell Miller and Filip Hrgovic after losing to Usyk, but Joshua went into the fight as a heavy favourite to regain the title.

Joshua, who lives in north London, was more used to fighting in big stadiums than Dubois, and he seemed more at ease in front of a large, expectant crowd that was set in the mood by a guest appearance from Liam Gallagher, who sang a number of hits from the recently reunited Oasis.

Dubois then sang a song about Joshua.

Dubois, who was promoted from interim world champion to full world champion after Usyk relinquished his IBF title in June, overpowered the challenger early in the fight.

Joshua started off calmly, but was taken down by an arcing right hand for his first count towards the end of the first round. Joshua briefly dropped his hands, inviting Dubois to throw a right hand. Joshua rose on wobbly legs, but was saved by the bell.

Joshua was still shaky in the second round as Dubois landed more punches. It wasn’t to be this easy for Dubois, who seemed on the verge of victory in round three. Joshua missed with a right hand and was caught with a counter left hook. He staggered back and rolled onto his ankle before Dubois landed more clubbing blows to leave Joshua in a heap and a count.

The bell came to Joshua’s aid again, but the former champion’s legs betrayed him again as he was given a second count early in round 4. He was fortunate not to receive a second count in round 4, but when he went down, no count was given.

Joshua, who was champion from 2016 to 2019 and then again from 2019 to 2021, was ready and Dubois obliged when he outpaced him with a right to the jaw that sent his rival tumbling to a dead stoppage in round 5.

Joshua, who had defeated his three previous opponents within striking distance, was left face down on the canvas and was knocked out by referee Marcus McDonnell as he tried to get up. It will be difficult for Joshua to bounce back from his most devastating defeat to date.