A bloodied Tim Tszyu has been cruelly denied in his quest to emulate his legendary father Kostya by becoming a unified world boxing champion after a sapping loss to towering American Sebastian Fundora.

Suffering his first defeat in 25 fights, Tszyu surrendered his WBO super welterweight belt and missed the chance to claim the vacant WBC strap at T-Mobile Arena in Las Vegas, which would have placed him among the sport’s elite.

Tszyu lost the fight in a split decision, with the judges scoring the fight 116 -112, 115-113, 112-116 in favour of Fundora.

The unlucky Australian’s fight derailed at the end of the second round when he was struck by the elbow of the 197cm tall Fundora, opening up a huge gash on his head.

Furious fans and pundits believed the fight should have been stopped shortly afterwards, including former world champ and Australian boxing legend Billy Dib.

‘This is ridiculous. This fight needs to be stopped. The amount of blood being lost is dangerous,’ Dib posted on X.

Tim Tszyu was cut by an accidental elbow early in the bout with Fundora

Some fans and pundits believe the bout should have been stopped then, like former world champion Billy Dib and ex pro boxer Gabriel Rosado

Boxing commentator and presenter Ben Damon was also shocked the fight went on.

‘No point having a doctor if they aren’t willing to stop a fight when one man has been hit by an axe. Unbelievable this wasn’t stopped at the end of 2,’ he posted.

Former pro boxer Gabriel Rosado also felt Tszyu was hard done by, saying the fight doctor or referee should have called a halt.

‘It’s not fair to Tszyu to fight with an injury caused by an illegal blow,’ he said.

But Tszyu was gracious in defeat.

‘Look, I told you, I’m an old throwback fighter whatever circumstances. I couldn’t see but all credit belongs to the man who won tonight,’ Tszyu said.

‘These things happen. The momentum was rolling. I was swinging hard in the first rounds and then ‘boom’, you’re blinded completely.

‘But, look, this is boxing. This is part of the sport and it happens.

‘Congratulations to Fundora – he’s the new king at 154 (pounds).’

The world champion had dominated the opening exchanges, putting his tall-timber opponent on the back foot with some heavy right-hand blows.

Despite blood pouring down his face, Tszyu was cleared to continue by the fight doctor but Fundora took advantage of the Australian’s lack of vision to level the score.

With both fighters covered in blood – Fundora’s nose was also gushing – the Australian continued to search for a way to bring the battle to an early end.

Fundora played it smart by trying to attack Tszyu’s head while the Sydney warrior, using his gloves to wipe the blood from his eyes, was unable to connect in his usual fashion.

With Fundora edging ahead, the fight doctor again checked the cut at the start of the seventh round but gave the green light for the bout to go on.

Both fighters were covered in blood throughout most of Sunday’s contest

Fundora used his range well and managed to get the points decision over the Aussie

Like a gladiator, Tszyu battled on as he hunted a knockout blow but, hindered by the blood flow, he was unable to stop the Californian.

Fundora’s win sees him join his younger sister Gabriela as a world champion after she captured the IBF flyweight world title earlier this year.

‘We’ve been praying for this moment a long time,’ Fundora said, adding that he wasn’t surprised by Tszyu’s courage.

‘I’m just happy Tim Tszyu gave me the opportunity and my dream came true.

‘He’s a world class fighter. He was a world champion for a reason. The way I won my belt, it’s an honour to share the ring and make history with him.’

A win for Tszyu would have meant that he and his father Kostya joined Leon and Corey Spinks as only the second father-and-son duo to become unified world boxing champions.

The towering American thanked Tim Tszyu for giving him the chance

He was also looking to set up a mega fight against either pound-for-pound king Terence Crawford or former unified welterweight champion Errol Spence Jr, with a pay cheque of $US10million ($A15.3million) on the table.

‘Look, I’ll bounce back,’ Tszyu said.

‘I showed up still, no matter what (injury I had), and I always bring the fight.

‘I was given one week (to prepare), no excuses, but I’ll fight whoever, whenever.

‘Even Errol Spence, who’s here. I’ll fight him as well.

‘Even Terrence Crawford, man. You want a good scrap, You know who to call?’

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.