Anthony Joshua has endorsed Oleksandr Usyk for rolling the dice in pursuit of world heavyweight title glory despite the Ukrainian's limited experience in the blue riband division.

Usyk, 34, was the undisputed ruler at cruiserweight before setting his sights on the highest weight category, in pursuit of greater prizes, recognition and fortune, but he has had just two fights since October 2019.

Relatively-unheralded American Chazz Witherspoon retired on his stool after seven rounds while British veteran Derek Chisora had moments of success last year only to lose a close unanimous decision.

Rather than take more time to settle - like Evander Holyfield before him - Usyk is gunning for Joshua's WBA, IBF and WBO crowns on Saturday.

While Joshua recognises his WBO mandatory is taking a gamble at the Tottenham Hotspur Stadium, where about 60,000 fans are expected to attend, the Briton thinks his opponent is better knowing now whether he has what it takes.

"When Holyfield came up to heavyweight I think he had six fights at heavyweight before he fought for the championship belt," Joshua said.

"Usyk's fought two heavyweights, he's jumping in at the deep end early on.

"But good luck to him, he must believe in himself. He wants to be at the top end early.

"It's better to swim deep - get in there and get on with it - rather than tread water.

"You could still end up drowning anyway."

Joshua will have noticeable advantages in height and reach and is expected to be heavier than his fellow London 2012 gold medallist.

"Advantages physically is one thing but it doesn't make the world's tallest man the heavyweight champion of the world... ," Joshua said.

"This is heavyweight boxing and I'm the heavyweight champion of the world.

"I don't play games. I'm here to win."

Usyk will attempt to follow in the footsteps of compatriots Vitali and Wladimir Klitschko in winning a world heavyweight belt.

Still only 31, Joshua, who is taking on Usyk after a prospective clash with WBC champion Tyson Fury fell through, believes he still has several of his best years ahead of him.

"Forty seems like the age where they're like 'OK, you've done this for a long time now, champ'. (Between) 36 to 40 is when I start making decisions in terms of what I do with my career," he said.