Tony Bellew has secured one of the biggest upset victories in British boxing history after David Haye was withdrawn in the 11th round of their fight with a suspected Achilles injury.
In the sixth round of the grudge match, Haye lost his balance and appeared to suffer the injury which left him barely able to stay on his feet at London's O2 Arena.
He carried on for another five rounds, struggling for balance and clearly on the verge of exhaustion, before he was finally pulled out by trainer Shane McGuigan after he was knocked nearly out of the ring by Bellew.
Haye, 36, had been a huge favourite for the contest and enjoyed initial success in the early rounds until suffering the injury.
But he refused to quit despite offering only a token defence, before Bellew landed a series of punches that knocked his opponent through the ropes in the 11th round and the contest was ended by the trainer.
The defeat will fuel speculation that former WBA heavyweight champion Haye will retire from boxing after his third loss in a 31-fight career.
He refused to blame his injury and instead praised an opponent he had subjected to a stream of insults in the build-up to the fight.
He said: "Tony was a great fighter, that's what went wrong.
"I wanted to do a demolition job but this guy has the heart of a lion. I didn't expect him to have the chin and durability that he had."
Bellew, 34, was fighting up two weights and giving up 11lbs in his first professional bout at heavyweight. He was a 4-1 outsider before the fight.
He said: "I am the champion of the misfits, and tonight I have taken my glory."