Anthony Joshua missed out on the chance to become a three-time heavyweight world champion after he was stopped by British rival Daniel Dubois in the fifth round.
Dubois, 27, knocked down Joshua towards the end of the opening round with an overhand right to the 34-year-old’s chin.
The IBF heavyweight champion then dropped Joshua at the end of round three and twice in the fourth.
A right hook ended the fight with a knockout for Dubois’ first defence of the title.
The fighters went toe to toe at London’s Wembley Stadium in front of a record 96,000 fans.
‘We came up short’
Minutes after retaining the IBF championship, Dubois shouted to the crowd “are you not entertained?” before saying: “I’m a gladiator, you know?
“I’m just a warrior to the bitter end. I’m just ready to go. I want to go to the top level of this game and reach my potential. God bless you all.”
Joshua said the loss would not stop him from rebuilding despite admitting “we came up short”.
“You know I’m ready to kick off in the ring, but I’m going to keep my cool, keep very professional, and give respect to my opponent,” he said.
“I’m always saying to myself I’m a fighter for life… We keep rolling the dice. I had a sharp opponent, a fast opponent and a lot of mistakes from my end, but that’s the game.”
Hearn: AJ will want rematch
Promoter Eddie Hearn then said “it was the first round” where Joshua lost, “after that he was fighting on heart and desire”.
Hearn added: “When you are in there with a massive puncher this is what can happen. He never stopped trying to get up, even when he couldn’t get up.
“Daniel deserves credit, he’s a real world champion. Congratulations to him… I’m sure [Joshua will] exercise that rematch clause, it’s a given, it’s a dangerous fight because he’s growing in confidence all the time but he’ll believe he can beat him.”
British champion Dubois, who before tonight had never fought at Wembley, was elevated to the IBF title holder after Oleksandr Usyk relinquished the belt.
Joshua outweighed Dubois by four pounds, despite a career-heaviest weight for his rival, ahead of the fight.
Among those watching was Tyson Fury, the former WBC heavyweight champion, who took a ringside seat.
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Fury is set to fight Usyk for the other three titles in a rematch on 21 December.
Ahead of the fight, Liam Gallagher played some of Oasis’ biggest hits to the sold-out crowd.
The 52-year-old frontman walked on to a massive cheer and said “yes Wembley vibes in the air,” before launching into Rock ‘N’ Roll Star, Supersonic and Cigarettes & Alcohol.
He and Noel Gallagher will play Wembley for their first of seven reunion shows at the stadium on 25 July – 307 days away.
Other famous faces ringside were Irish MMA fighter Conor McGregor, former boxer Ricky Hatton, Spice Girl Emma Bunton and Love Island presenter Maya Jama.