Trusted uncle-trainer Igor Goloubev and 76-year-old Boris Tszyu call the shots in Tszyu's life - inside and outside the boxing ring.

Believing his father, a former undisputed world junior welterweight champion, is behind Tszyu's own rise to prominence is an easy assumption for sports fans.

But the 28-year-old has set the record straight, declaring his grandfather has been the making of him.

"He's everything. Everything!" Tszyu told AAP ahead of his world-title stoush in Sydney on Sunday with American Tony Harrison.

"Every little aspect of boxing and my life, my grandfather's in it.

"My grandfather is the key piece. Not just for my career, but Dad's career too.

"He's the foundation, he's the block, he's the one who pushes it."

While Kostya moved back to Russia a decade ago, Tszyu consults with his Sydney-based grandfather three or four times daily.

Even when he set up training camp in the USA late last year ahead of his scheduled showdown with Jermell Charlo - before it was cancelled after the undisputed world champion broke two bones in his left hand - Tszyu fielded dozens of Whatsapp calls from Boris.

With good reason.

The meticulous mentor keeps a log of both his son's and grandson's careers, comparing every minute detail, right down to how many ropes they each skipped at what age, their weights, when and what they eat and, of course, their records in the ring.

Given that Kostya had some 300 amateur fights before turning professional, that's some record keeping.

Now, with Tszyu's younger brother Nikita also fighting on Sunday against compatriot Bo Belbin, two members of Australia's most famous boxing family will feature on the same card for the first time.

That's more work for Boris.

"He's always there. He's the rock behind me and Nikita. Everyone needs their rock and he's the one," Tszyu said.

Tszyu often doesn't even know when he's required to train. He merely waits for a quiet nod of the head from Boris before rising for work.

It's that stringent routine and unwavering sense of discipline that has not only earned Tszyu a shot at super-welterweight title glory but also a reputation as one of the most impressive and fittest athletes in the country.

Much of the credit for Tszyu's supreme conditioning and nous in the ring can go to Goloubev, Kostya's brother-in-law, who on Tuesday revealed he'd put his charge through some 333 sparring sessions in the lead-up to his date with destiny at Qudos Bank Arena.

"In terms of tactics, the main man's Igor," Tszyu said.

"He's the one that puts in a lot of work - like, a lot - and he's built a lot of fighters. It's crazy."

That includes Kostya, who remains very much a part of Tszyu's life - just not quite in the way many may think.

"My dad gives me life advice and that's what's needed," the Sydney slayer said.

"He's not my boxing coach. Igor's my boxing coach and Igor started with me since the day I started boxing, so since when I was young.

"Igor was the on the pads. Igor was the one building me and moulding me, so the credit belongs to that man.

"I can always call my dad and ask him for little advice, but it's not technical boxing."

Very much a man on a mission, Tszyu is bidding to become only the sixth boxer in history to emulate his father by becoming a world champion.

Australian Associated Press