Alex Leapai's trainer believes if the Samoa-born boxer can win the world heavyweight 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 Ukrainian Wladimir Klitschko in Germany next weekend.
Thornberry has dismissed claims from Klitschko's camp that Leapai isn't fit to step into the ring and says Klitschko himself is wary of the 34-year-old.
Leapai leaves for Germany on Saturday.