Tim Tszyu is set to go to war again with Sebastian Fundora by enacting a rematch clause after the American "Towering Inferno" stole his thunder to become an unlikely unified world champion.
Tszyu's plans for global boxing domination were put on hold in Las Vegas when he was cruelly denied in his quest to emulate his legendary father Kostya.
Suffering his first defeat in 25 fights, Tszyu relinquished his WBO super welterweight belt and missed the chance to claim the vacant WBC strap at T-Mobile Arena and take his place among the sport's elite.
Tszyu lost the fight in a split decision, with the judges scoring it 116 -112, 115-113, 112-116 in favour of Fundora.
The Californian's win sees him join his younger sister as a world champion after Gabriela Fundora captured the IBF flyweight world title earlier this year.
The unlucky Australian's challenge derailed at the end of the second round when he walked into the elbow of 197cm Fundora, opening up a huge gash on his head that left him blinded by blood for the remaining 10 rounds.
Tszyu comfortably won the opening two rounds but the script went out the window after the cut as Fundora took advantage of the Sydney slugger's lack of vision to change his tactics to narrowly come out on top.
If the fight had been stopped by the doctor when he suffered the blow, it would have been declared no-contest.
Had it been stopped after the fourth round, it would have been a draw, with the boxers winning two rounds each.
But the 29-year-old had no regrets that his corner didn't push for those outcomes and didn't want to use it as an excuse for his loss.
"I took Fundora on a week's notice - I am who I am - I'm a warrior and this is what I do," Tszyu said, with blood still dripping down his face at the post-fight press conference despite 10 stitches being inserted.
"A bit of blood never killed nobody.
"It was a good war and I started off well; Fundora's an awkward opponent, very tall and rangy and flicks that jab.
"I feel like I did isolate his punches and was able to to feel him out and I think the cut did play a part a bit as I couldn't see anything but no excuses, the better man won."
While Tszyu lost his world title, he won plenty of fans in his gutsy US debut by his decision to take on Fundora with 12 days' notice after injury to his original opponent Keith Thurman.
Given Fundora's 23cm height advantage and the switch to fight a southpaw, it presented the biggest challenge of Tszyu's career.
The loss has dented plans for a mega fight against either pound-for-pound king Terence Crawford or former unified welterweight champion Errol Spence Jr, with a pay cheque of $US10 million ($A15.3 million) on the table.
Crawford tweeted after the fight: "You lost sir gotta work yo (sic) way back up" while Spence entered the ring and talked up plans to take on Fundora.
As the WBO's "super" champion at 147 pounds, Crawford has positioned himself for a mandatory shot at a new weight and the fight with Fundora could be ordered this week.
Fundora's promoter Sampson Lewkowicz said after the fight that while there was a rematch clause, Tszyu might have to wait while Fundora cashed in on his new status.
But Tszyu's promoter George Rose was adamant they could insist on the rematch.
"He (Lewkowicz) knows there's a rematch clause and, if we want to take it, we will take it," Rose said.
"I'd love to see Tim take that and win those belts straight back so I'm happy for a rematch to happen next and good luck trying to get out of it."
Tszyu's defeat ended a miserable 24 hours for Australian boxers with Liam Wilson and Michael Zerafa also losing their world-title fights on a huge weekend in the US.
