Frazer Clarke believes that Daniel Dubois needs Oleksandr Usyk to have "a little bit of an off night" if he is to become the undisputed heavyweight champion of the world on July 19.

Usyk (23-0, 14 KOs), the WBC, WBA, WBO and Ring champion, and IBF titleholder Dubois (22-2, 21 KOs) will fight at London's Wembley Stadium.

Fully recovered from the shocking first-round stoppage to Fabio Wardley in October, Clarke (9-1-1, 7 KOs) is doing all he can to reclaim his standing in the division.

The 2020 Olympic bronze medallist returned in April, knocking out Ghanaian veteran Ebenezer Tetteh inside a round, and during an interview with talkSPORT revealed that he recently spent some time in camp with the unbeaten unified titlist.

Clarke, 33, also shared the ring with a teenage Dubois during their time on the Team GB boxing team in Sheffield and is ideally placed to give his opinion on the upcoming rematch.

"He's just a fantastic operator. I've been in the ring with so many champions over the years and he's right up there with the people I've been in with," Clarke said of the time he spent with Usyk.

"It's the subtle things that you wouldn't notice that he does well. His level of professionalism — as a fighter myself — it's something you take such a lot from. I got a small experience with him for a few rounds but took a lot from it. A great champion and great fighter."

In August 2023, Usyk outboxed Dubois for long periods, but the Londoner still believes he was hard done by when a shot to the midsection sent Usyk to the canvas in the fifth round.

Rather than administering a count, referee Luis Pabon ruled that the punch had strayed below the belt and, after taking around four minutes to regather himself, Usyk ramped up the pressure on a disheartened Dubois and persuaded him to take a knee early in the ninth.

In the intervening two years, Dubois — The Ring's No. 2-ranked heavyweight — has rebuilt himself and racked up stoppage victories over then-unbeatens Jarrell Miller and Filip Hrgovic as well as two-time unified champion Anthony Joshua, becoming IBF champion in the process.

Usyk, meanwhile, went on to become the first undisputed heavyweight champion of the 21st century by outpointing Tyson Fury and repeated the feat in a rematch.

Still, the brilliant Ukrainian is now 38. Although there have been precious few signs of slowing down, he's starting to enter that dangerous territory where he could begin to show signs of wear and tear.

"That's what Daniel's hoping for sure and I do give him a chance," Clarke said.

"He's a fantastic fighter, Daniel Dubois and the way he hits, powerful, he's one of the biggest punchers in the division so he's got a chance. But, he's up against one of the best that we've ever seen so he needs to have the best night of his career and maybe hope that Usyk has a little bit of an off night."