Emanuel Steward believes that Wladimir Klitschko still has another three years at the top.
The boxing Hall of Fame trainer is currently preparing the Ukrainian for his world heavyweight title defence against Jean-Marc Mormeck on Saturday.
Steward has said that training has gone well and the 35-year-old is in the shape of his life.
"I think Wladimir's at his peak right now," Steward told Sky Sports.
"The way he's looking in terms of his speed and punching power and his desire and interest in the sport he will stay at that peak for at least another three years."
Steward previously trained Britain's undisputed heavyweight world champion Lennox Lewis.