Tony Bellew claimed a stunning upset victory over bitter rival David Haye, battering the former world champion to an 11th-round stoppage as bedlam gripped the O2 Arena.
An ill-tempered build-up was laid bare as both men swung from the hip with bad intentions, but WBC cruiserweight champion Bellew - fighting in the highest weight division for the first time in his professional career - upset the odds to outlast Haye, whose designs for a shot at IBF ruler Anthony Joshua now lie in tatters.
Indeed, the bad blood gave way to a warm embrace, mutual respect and talk of a rematch after Haye had tumbled through the ropes and his corner threw in the towel, an ending few other than Bellew - who moves on to a professional record of 29 wins, two defeats and a draw - foresaw.
Haye (28-3) seemed inconvenienced by an ankle injury after a tide-turning sixth round but pledged to offer no excuses at the conclusion of a breathless contest.
Finesse in the early stages - initially and unexpectedly from Bellew, who ducked under Haye's clumsy advances and landed with his favoured left hook - gave way to a sapping and brutal struggle.
Haye's status as the natural heavyweight appeared to be draining Bellew by the end of the fifth, but a clash of heads that left the 34-year-old Liverpudlian on the floor in the next session proved pivotal.
Not for the first time in his career, the red mist appeared to smother Bellew and he was sparked into furious trading. It thrillingly worked in his favour - Haye was twice ruled to have slipped but a knockdown was called as he stumbled to the canvas for a third time.
The 36-year-old struggled for mobility thereafter and it led him to dark places in the seventh as Bellew unfurled an unrelenting assault.
He barely let the Londoner leave his corner, with the only worry for Bellew's team that their man might have punched himself out.
The pace inevitably slowed, Bellew playing the matador in the eighth but, when Haye steadied himself for a final assault he missed badly once more and left himself open to Bellew's finishing salvo.
Haye answered questions over his heart by clambering back through the ropes but coach Shane McGuigan saved him from his still flickering pride.