Tyson Fury was denied one of the greatest comebacks in history when his WBC heavyweight title fight against Deontay Wilder at the Staples Center in Los Angeles was scored a draw.
Despite two heavy knockdowns, a victory greater than even that over Wladimir Klitschko and after only 14 rounds following over two-and-a-half traumatic years of inactivity was prevented by harsh scores of 115-111, 112-114 and 113-113, despite him impressively outboxing the champion, who retains his title.
Fury was first knocked down in the ninth, and again in the 12th when he appeared out cold, but he returned to his feet and recovered enough to survive to the final bell.
If Wilder's explosive power already posed a significant threat, the biggest question surrounding Fury's chances was whether he had truly recovered from that period, in which he admitted to taking cocaine, becoming suicidal and lived to such excess he reached an estimated 27 stone.
The answer to that ultimately became clear when, even as their fight progressed into the dangerous final rounds, he somehow performed with the same sharpness that inspired his memorable victory over Klitschko, even recovering from the second knockdown to end their fight on top.
An affair that was expected to be cagey instead produced 12 thrilling rounds that made a rematch inevitable even before the scores were announced.
They are likely to fight again next spring, when Fury would become the favourite, posing a greater threat to Anthony Joshua's status as the world's leading heavyweight.
In front of a 17,698-strong attendance, both fighters entertained from the opening bell when they both threw threatening punches and Wilder landed a hurtful right as they briefly fought toe-to-toe.
Demonstrating his confidence with early periods of showboating, Fury often became the more consistent aggressor and while resisting occasional powerful punches he also made the world's most dangerous puncher swing and miss.
The champion began to fall short with jabs, and watched Fury comfortably take a left uppercut as he pursued the knockout while his left eye began to swell.
Fury was gradually building a convincing lead into the fight's second half as he landed with several straight rights, even when Wilder's occasional successes looked the more hurtful.
The final four were always going to be the most threatening when he tired and his reflexes may have waned, and so it gradually proved when after taking a left-right combination, a right hand to the back of the head knocked him to the canvas.
Fury had twice previously recovered from knockdowns to remain undefeated, and this time the 30-year-old fought back and stuck out his tongue in a sign of his self-belief.
Further success in the 10th round when he landed with both lefts and rights and hurt Wilder, 33, again gave him the momentum when it became increasingly clear the champion was running out of time.
He resiliently then retained his title when, despite his exhaustion, a big right sent Fury tumbling and a further left secured so heavy a knockdown his admirable challenge seemed over.
The Briton instead survived as the tired Wilder struggled to force another attack and the stoppage, meaning an immediate rematch will be next.
It was after the unprecedented high of his victory over Klitschko that Fury fell into the darkest period of his life. This performance showed he has convincingly recovered from that, and he may even again prove the best heavyweight in the world.
Fury's compatriot and promising fellow heavyweight Joe Joyce had earlier secured his seventh professional victory when he stopped Joe Hanks of America in two minutes and 25 seconds.
There was also a fourth-round defeat for British light-middleweight Jason Welborn, who was stopped by a bodyshot from defending IBF and WBA champion Jarrett Hurd.