Nikita Tszyu in TKO win on huge day for boxing family

Emerging star Nikita Tszyu has maintained his unbeaten professional boxing record with an emphatic TKO victory over fellow Australian Bo Belbin.

On a mammoth day for the Tszyu family, the 26-year-old floored Belbin early in the fourth round with a heavy left before the referee stopped the fight half a minute later following another flurry of head shots from the so-called "Butcher".

Belbin was already sporting a bloodied nose and nasty cut under his left eye after copping a battering in round three.

Having already taken down Ben Horn, the younger brother of former WBO welterweight champion Jeff Horn, Tszyu stopped short of calling this his best win yet.

But he was mightily satisfied at snapping Belbin's own unbeaten record in the Tasmanian's eighth fight.

"I'm proud of it. I stayed composed during some tough times in that fight," he said.

"He caught me early but I stuck to my game plan. We're like brothers in a way - with the same mindset - and I truly respect him."

Tszyu's latest super-welterweight victory improved his record to 5-0, with four knockouts.

Sunday's bout at Sydney's Qudos Bank Arena marks the first time Tszyu and his superstar brother Tim have fought on the same card.

Tim is taking on American Tony Harrison for the interim WBO super-welterweight title, hoping to join his legendary father Kostya as a world champion.

"This was the entree. Get ready for the main course," Tszyu said.

"The atmosphere is electric. Tim is about to bring home a world title and you're all here to witness it, so let's get behind him."

In the co-main event, Paulo Aokuso plundered and played with Yunieski Gonzalez (21-6, 17KO), winning comfortably on points to move to 4-0 and claim the vacant IBO Inter-Continental light-heavyweight title.

Aokuso has his sights set on beating compatriot Jeff Fenech's national record by claiming a world title in just six professional fights.

But, despite dropping the veteran Cuban midway through the 10-round tussle, the Australian Olympian was denied the showtime stoppage that would have helped his cause.

In another feature bout on the undercard, classy Sam Goodman (14-0, 7KO) retained his IBF Inter-Continental and WBO Oriental super bantamweight titles with a unanimous points win over Ireland's Sydney-based former world champion TJ Doheny (23-4, 17KO). 

And Rohan Murdoch (27-2, 19KO) won a split decision over a livid Issac Hardman (13-2, 11KO) to claim the IBF Australasian super-middleweight title.