BRISBANE - Alex Leapai's trainer believes if the Australian can win the world heavyweight boxing title, it will be as big an upset as when James "Buster" Douglas defeated Mike Tyson.
Douglas shocked the boxing world in 1990 when he knocked out then undefeated world champion Tyson in Tokyo.
And Noel Thornberry expects a similar reaction if his man can stop legendary Ukrainian Wladimir Klitschko in Oberhausen, Germany on April 27 (AEST).
Leapai, the Samoan-born father who has gone from jailbird to world title contender, goes into the bout against the WBO, WBA, IBF and IBO title holder as a huge underdog.
His potential to land a knockout blow is seen by many as the only hope he has against Klitschko, who hasn't been beaten in 10 years.
Thornberry has dismissed claims from Klitschko's camp that Leapai isn't fit to step into the ring against the champ as nothing more than parrots "squawking" and says Klitschko himself is wary of the 34-year-old from Logan, south of Brisbane.
"He's fully aware of Alex's power and he won't be underestimating Alex by any means," Thornberry said.
"Alex believes this is his destiny and I believe it is too.
"I honestly believe that Alex's style is the sort of style that will break this guy down."
Leapai has shed six kilograms of fat during his preparations for the fight and nothing is being left to chance in his preparation.
Leapai held his final sparring session in Brisbane on Thursday and will avoid any heavy contact from now until the fight.
He'll also keep his body clock on Australian time while in Europe.