Kell Brook was stopped by Errol Spence Jr to lose the IBF world welterweight title in dramatic fashion at Bramall Lane.
Brook, who underwent surgery on a broken right-eye socket eight months ago, sustained a heavily swollen left eye midway through the bout and never fully recovered.
The Sheffield fighter was put down in the 10th when Spence ruthlessly went to work on the eye but roared on by home support, rallied bravely.
But in the 11th after visibly blinking his left eye in an attempt to clear his vision, Brook took a knee when not under heavy attack and although he rose on a nine count, referee Howard Foster ended the contest.
There were boos of disappointment by the 27,000 in attendance at the home of Sheffield United. Brook, wearing shorts sporting the colours of the club he supports, looked accepting of his situation, while Spence was already celebrating during the count, sensing his rival could not continue.
The 27-year-old was impressive in what was an incredibly close contest until the late stages but he pounced when he realised Brook was struggling with injury, savagely jabbing at the eye and clubbing away at the body with follow ups.
When Spence put his rival down in the 10th, Brook’s quick leap to his feet intimated he was suffering more with the chaos of injury than through the power of punches coming his way.
But promoter Eddie Hearn believes his fighter might have suffered a suspected broken eye socket, a cruel blow given the road to recovery he faced in recovering from the severe damage he suffered to the other eye against Gennady Golovkin eight months ago.
“I couldn’t see out of the eye, so I had to stop,” said Brook, who later went to hospital for treatment on his eye. “I thought it was very competitive, he won a few rounds, I won a few rounds, I felt I was in the fight,”
“I’m gutted, devastated that in front of my own fans I’ve lost my belt.
“When I walked out of the tunnel and saw everybody, it was amazing. I’m so proud of myself for having brought this to Sheffield. I got hurt when I got put down, I’m a warrior and when you can’t see, there’s nothing you can do.
“I will fight anyone, what the fans want, where the money is. I’m sorry for everyone that come out. We made a great night for Sheffield and brought a lot of money into Sheffield. I hope everyone has had a good night.”
‘The end of Brook’s career?’ – Analysis
BBC Radio 5 live’s boxing correspondent Mike Costello
It never ceases to amaze me how much these men are willing to give. Even when Brook went down tonight it was only because he physically couldn’t see out of his eye.
I’ve got to say I think that will be the end of his career. What is the point of him coming back at a lower level? If he comes back at this level he’ll just do further damage.
What now for Brook?
In returning to welterweight from that middleweight defeat to Golovkin, Brook looked solid at the weight throughout. Many commentators believed that in losing over a stone to make the 10st 7lbs limit, Brook would run out of steam against a much-hyped opponent.
He was the underdog with bookmakers’ but no one could say he was not competitive until injury occurred. Three rapid-fire blows in the fifth backed the younger fighter to the ropes but slick footwork and a cool head saw Spence repeatedly match the champion even at points where he looked vulnerable.
Brook, following a lengthy lay-off with this latest injury, will now surely move up a weight division. He had spoken of being “stubborn” in not giving up his title at 147lbs but that honour is now gone.
A big-money contest with Amir Khan – who was ringside – could appeal if the parties can end seemingly years of failed negotiations. A move up a division is surely therefore more likely and some in Brook’s camp would be relieved to see an end to the days of big weight cuts. For now though, they will hope his eye injury leaves him with career options at all.
Spence lives up to the hype
It is now 10 fights since Spence has needed a bout to go to the scorecards and he is now 22 fights unbeaten, with 19 coming via stoppage.
The presence of major US TV network Showtime illustrates the belief his country has in him. The likes of Sugar Ray Leonard have called him the “real deal” and with this win, the platitudes will flow further.
A London 2012 Olympian, he has now built on his pedigree and will surely target WBA and WBC champion Keith Thurman in an all-American unification bout.
His options are plentiful, while Brook’s could hinge on the success of another stint on the operating table.
“I give Kell all the credit, and the hardcore fans here,” said Spence Jr. “A true champion goes anywhere to fight. He has gone to America and fought so I came here.
“I didn’t feel that sharp tonight, but true champions still win.
“He was tired, fatigued but kept firing shots. The goal is to unify and become undisputed welterweight champion of the world.”