George Groves says he wouldn't be at all surprised if Anthony Joshua's reign as the unified heavyweight champion of the world is ended by Oleksandr Usyk this weekend.  

Joshua, 31, puts his WBA, WBO and IBF belts on the line against mandatory challenger Usyk at the Tottenham Hotspur Stadium in London on September 25. 

The Brit is favourite to keep his belts and line up an all-British derby against Tyson Fury in 2022. 

But Groves believes Ukrainian Usyk has the stamina to cause an upset in Saturday's world heavyweight title fight against Joshua.  

"Technically, Usyk is brilliant," Groves told the 5 Live Boxing podcast

"He showed that in unifying the cruiserweight division in great fights and I believe he could be Joshua's toughest test to date. This is the first fight when I wouldn't be surprised if Joshua got beaten.

"Joshua has fought [Wladimir] Klitschko and been in with Joseph Parker and also been beaten [by Andy Ruiz] and the only question mark for Usyk is: Is he big enough to compete with AJ?

"If Usyk keeps a high pace and makes Joshua miss with a lot of shots, that will work to Usyk's advantage as he has probably got a better engine.

"Joshua is a phenomenal athlete with tremendous punching power and strength but has a tendency to tire out if the pace is uncomfortable for him."

'You don't want Usyk having any confidence'

However, Groves has also mapped out Joshua's path to victory.  

"If I was Joshua, I would take control of the ring and try to dominate and bully off the front foot," he replied when asked about how he would approach the fight with Usyk.

"Usyk will want to be off the back foot for the first couple of rounds, then try to pepper Joshua.

"If I was in the Joshua camp, I would say: You want to keep this guy in his box. You don't want Usyk having any confidence, so hit him hard and early.

"In the first three rounds, you want to land something big on him."

Anthony Joshua defends his titles against Oleksandr Usyk on September 25 at the Tottenham Hotspur Stadium in London

Meanwhile, Hall of Fame boxing promoter Frank Warren has also been impressed by what he has seen of Usyk so far and says the Ukrainian may win the fight on points if it goes the distance. 

"Anthony Joshua must be the favourite for the fight," Warren told iFL TV

“He’s the bigger guy and he’s a bigger puncher.

“Having said that, if he [Joshua] doesn’t get rid of him, and if he’s still there after five or six rounds, then it gets to the end of the fight, if that goes 12 rounds, I would fancy Usyk to get the decision because to get there, he’s going to have to outbox him.

“He proved it at cruiserweight. He was fantastic, and he’s made his mark in that weight division. He was a superb cruiserweight.

“He’s done everything you could ask for [at heavyweight]. He’s come up a weight and fought Chazz Witherspoon, went seven rounds, and he fought Derek Chisora.”

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