A family illness threatens to deny Kostya Tszyu the chance to watch his son Tim try to create a slice of boxing history.
The great Kostya had planned to walk Tszyu into the ring for his unified world title bout with Jermell Charlo in Las Vegas in January before the blockbuster was cancelled after the American broke his left hand in training.
Tszyu will instead fight Tony Harrison in Sydney on March 12 for the interim WBO super-welterweight belt.
But Tszyu told AAP that Kostya, a former unified light-middleweight world champion, is stuck in Russia caring for his ailing half sister.
"My little sister's a little bit sick right now so I think he's looking after her at the moment," Tszyu said on Wednesday.
"So we'll see how it all pans out. Not sure, man."
The 28-year-old is bidding to follow in Kostya's footsteps and join an elite group of father-son boxing world champions, including Julio Cesar Chavez and Julio Cesar Chavez Jr and Leon and Corey Spinks.
Even if Kostya isn't at Sydney's Qudos Bank Arena on Sunday week, Tszyu said he'd received the same old advice as usual in how to beat Harrison.
"Just to be smart. Try and not get hit too much," Tszyu said.
"Boxing's quite simple, man. Hit your opponent more than he hits you."
Harrison (29-3-1, 21KO) has been mouthing off about Tszyu (21-0, 15KO) being out of his league, but the Sydney slayer is confident he will have the last laugh.
"That's a good feeling when he thinks he's in with a basic boxer," Tszyu said.
"That's what Australia's got - we've got this talk in America that we're only basic, that we lack skills and are all toughness.
"That's wrong, man. We've got great ability here, we've got great talent here and we're here to shock the world."
The cancellation of his showdown with Charlo has left Tszyu without a fight since last March.
But he doesn't think ring rust will be a problem.
"Right now I'm just itching. I've got this fire burning in my belly. Just like a hungry, hungry lion ready to eat," Tszyu said.
"I've got an empty stomach and I'm ready to eat and fill it up (with Tony Harrison)."
The winner will face Charlo later in the year with the opportunity to unify the super-welterweight division.
Tszyu has no doubts he will get his shot at Charlo, whose only ever defeat came against Harrison in December, 2018.
The home-town favourite expects Harrison's renowned right jab to pose the biggest challenge but expects to be too strong physically for the American.
"He's tall. Look at me. The broadness of myself compared to what he is - he goes up, I go out," Tszyu said.
"We're completely different body shapes and, as they say, you twitch it in half when you've got a body like that in front of you.
"There's plenty of bones to break as well."
