Victory over Takeshi Inoue in Wednesday night's much-anticipated super-welterweight showdown in Sydney would improve Tszyu's impressive unbeaten professional record to 20-0 since debuting four years ago.

For all his accomplishments, including winning his first world title in just his 14th bout and then successfully defending the International Boxing Federation's light-welterweight belt four times, Kostya Tszyu did not win all of his opening 20 fights.

The undisputed multiple world champion's 19th fight against Leonardo Mas in 1997 was ultimately declared a controversial no-contest after Tszyu floored the Puerto Rican three times in Las Vegas.

Then American Vince Phillips stripped Kostya of his strap in Tszyu Snr's 20th fight in Atlanta City four months later - when Tim was only two years old.

Almost a quarter of a century on and Tim Tszyu, while fast emerging from his father's giant shadow, humbly acknowledges he's not yet in the same stratosphere as his legendary father.

But the 27-year-old did enjoy a smirk after learning he had the chance on Wednesday to get one over his old man.

"Me and my dad aren't in competition," Tszyu told AAP before Tuesday's weigh-in.

"Long way to go. I'm still a baby in this sport."

Tszyu then quickly traded his smirk for a throat-slitting gesture after the making the weight at 69.52kg, slightly lighter than Inoue's 69.68kg.

I'm coming for his head," Tszyu said.

"I know how confident he is. I hope he's enjoyed his holiday here. It all ends tomorrow."

As he's been promising for the past week since arriving in Australia in supreme physical condition, Inoue (17-1-1) maintained for one last time he would brutally end Tszyu's undefeated run.

"I feel confident I can make this a really good fight," Inoue said.

"Yes, I do still feel I will knock him out. I see myself breaking his spirit and finishing him."

Tszyu, who has won 15 of his 19 fights by TKO, said: "Let him do what he wants. One thing I know is that I'm coming for his head, and his body, everything".

Tszyu is the WBO's mandatory No.1-ranked challenger for Argentine Brian Castano's light-middleweight title.

That blockbuster is slated for early next year.

But a loss to the Japanese slugger at Qudos Bank Arena would shatter those world-title ambitions.

Australian Associated Press