Heavyweight prospect Frazer Clarke believes veteran trainer Robert Garcia has revamped the overall mindset of Anthony Joshua for the upcoming rematch with WBO, IBF, WBA, IBO world champion Oleksandr Usyk.

Earlier this year, Joshua parted ways with longtime trainer Robert McCracken and ultimately retained the services of Garcia.

Many observers felt Joshua was not aggressive enough in his decision loss to Usyk, back in September of last year at Tottenham Hotspur Stadium.

The rematch takes place on August 20 in Saudi Arabia. The event will be carried by Sky Sports Box Office.

Clarke, a 2020 Olympic bronze medal winner, has observed a newfound motivation from Joshua in the British star's ongoing training camp.

"He's under no illusions. He's going to have to be the best he's ever been to beat Usyk. I think he's going to have to be better than he's ever been. Better than the Wladimir Klitschko night. I feel like he has to be Klitschko-esque. That night there were ups and downs and he had to come back. He might just have to do that," Clarke told Sky Sports.

"He's got every chance. From what I've seen him put in on a daily and a weekly basis, he's given himself every chance and that's all you can ask from a fighter in a camp. If you give everything you've got to give, with the experience and the skill he's already got, he's given himself every chance.

"There's a lot of people out there talking about Usyk being so good and this and that. He is very good. There's no doubt. He's a great fighter. But he's a human. If AJ hits him on the chin more than once, he's only human, he goes down, he probably doesn't get back up."

Clarke is expecting added aggression and physicality from Joshua when he steps in the ring with Usyk for a second time.

"I feel like [Joshua is] a nice guy. I think someone had to pull the bad guy out of him. I think Robert Garcia was good to do that. He pulled out the not give a sh!t about anyone apart from winning this fight. He's brought it out of him. This could be Britain's greatest night of heavyweight boxing. I feel like everyone's putting him as a massive underdog and he might just get outboxed for 12 rounds. But you'd be daft to bet again him," Clarke said.