Former heavyweight world champion Deontay Wilder looks set to retire from boxing after suffering a devastating knockout defeat to Zhilei Zhang in the main event of the Matchroom Boxing vs Queensberry Promotions event in Saudi Arabia.
The unique concept, which saw Matchroom's Eddie Hearn put five of his fighters up against Frank Warren's Queensberry stable in a team format, was swept by the Queensberry boxers, who won all five bouts.
The event was headlined by the heavyweight clash between Wilder and Zhang, and the once formidable 'Bronze Bomber' again looked a shadow of his former self. The American, who was dominated by Joseph Parker in his last fight in December, crashed to the canvas after being caught by a punishing right from Zhang in the fifth round and was counted out.
It was Wilder's fourth defeat in his last five fights and surely spells the end of a career that saw the Alabaman reign as the WBC champion for five years.
"I would like to thank every friend who came here over the world and fans in China, it is midnight there and you are watching me," Zhang, who lost his WBO interim champion status to Parker in his last fight, told DAZN.
"I lost to [Joseph] Parker, it was a fair loss. He was the better man that night. I've learned since then. As long as the bell doesn't ring, stay focused.
"I have to pretend Wilder didn't have a right hand and I successfully took it away. Wilder punches hard, I give him a lot of respect."
That fight was preceded by another major heavyweight bout as Britain's Daniel Dubois caused a minor upset to hand Croatian Filip Hrgovic his first professional defeat to claim the IBF's interim champion belt.
Referee John Latham intervened 57 seconds into the eighth round on doctors' advice at the Kingdom Arena with Hrgovic bleeding from cuts over the eyes.
Dubois could be elevated to world champion if Ukraine's undisputed world champion Oleksandr Usyk relinquishes the IBF title or is stripped by the sanctioning body.
The Londoner could also be lined up for a title fight with former champion Anthony Joshua, who was watching from ringside.
"I've heard the next opponent will be AJ, so bring it on," Dubois told DAZN after the outstanding performance of his career to date. "I'm anxious to become the best, this is my era and my time. I'm glad I've got this IBF belt and on to the next."
Hrgovic led the opening rounds but the blood started flowing from the second round and Dubois sensed events were going his way.
The Croatian looked out on his feet in the seventh, with Dubois landing some punishing blows and adding to the damage from the cuts, but somehow made it to the bell.
"The round before the last, I was getting to him. It was just coming together like magic," said Dubois, who admitted he had taken time to warm up. "It's all a learning experience. I’ve come from rock bottom last year and now we’re back on top."
Before that, Dimitry Bivol successfully defended his WBA light-heavyweight title against Libya's Malik Zinad, who had stepped in at three weeks' notice.
Saturday night's event was meant to be headlined by an undisputed bout between Bivol and unified champion Artur Beterbiev, which was not part of the 5-vs-5, but the Russian-born Canadian was forced to withdraw after sustaining a knee injury.
Instead, Bivol's fight with Zinad was inserted midway through the tournament and the Russian displayed all his class to secure a sixth-round stoppage.
"Of course I'm happy that I won. I won this fight great. My team are happy and I'm happy," Bivol, who extended his unbeaten professional career to 22 fights, told DAZN.
"We're professional boxers, we have to change our tactic at any moment and at any second in the ring and I had enough time to prepare.
"I believe that my power was with me every time, I didn't have doubts," he added after claiming his first knockout victory in more than six years.
Bivol's fight was preceded by a middleweight clash between the highly-rated Briton Hamzah Sheeraz and American Austin Williams, and Sheeraz demonstrated why he's being talked about as an imminent world champion with an 11th-round knockout - his 14th straight stoppage.
The only other world title bout of the event saw British fighter Nick Ball become a world champion at the second attempt by outpointing WBA featherweight belt holder Raymond Ford.
Ball was arguably unfortunate not to already be a world champion when his last fight against WBC title holder Rey Vargas ended in a controversial draw. However, there would be no denying him at the second attempt as Ball claimed a thrilling split-decision victory over his American opponent.
"I'm made up. I should be two-time [champion] but it's not the case. I'm the champ now so it doesn't really matter," Ball told DAZN. "My style is all action and putting pressure on and I did that well. It paid off.
"This is boxing, you're going to get hit. It's how you recover and come back, that's a true champion and that's what I am now. He's a tough man and a class boxer. I had to dig deep to get the belt."
The event began with an all-British light-heavyweight contest as Willy Hutchinson defeated Craig Richards via unanimous decision to set Queensberry on the path to a whitewash victory.
"I always we felt we picked a very strong guy. My guys were here to win and they did it in style. Some cracking fights, some close fights, fans certainly got their money's worth. It's a brilliant concept," said Queensberry's Warren.
When asked if they plan to replicate the concept, Warren added: "We do. We've been talking about it. Eddie will want revenge and we will see what happens but we are keen to do more."
Matchroom's Hearn said: "The main thing is the card was incredible, we knew it would be. I put on a brave face but I'm gutted. We kept clutching at straws here. 5-0 sounds better than 10-0. I want the rematch, I've enjoyed making this together.
"We loved doing this, tonight was incredible. We will run it back either in London or here."
