Usyk vs Chisora: Anthony Joshua has 'nothing to worry about' in Oleksandr Usyk, says Carl Froch

Anthony Joshua has 'got nothing to worry about' in Oleksandr Usyk, if the former cruiserweight king stays on course for a world heavyweight title fight, says Carl Froch.

The Ukrainian star is the WBO mandatory challenger for Joshua, but Usyk must firstly prove his credentials at heavyweight against Derek Chisora on Saturday night, live on Sky Sports Box Office.

Sky Sports expert Froch has been impressed with Usyk's sublime skills, but questions whether he has the size and power to trouble unified champion Joshua.

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"I don't think AJ will be worried," Froch told Sky Sports: "He will be watching him, probably thinking to himself, 'He's not big enough for me. I've got size and reach.' He'll be quietly confident, AJ, I think.

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"I really do think that AJ has got nothing to worry about in Usyk. I need to see how well Usyk performs against Chisora, before I can even mention him in the same breath as AJ. I'm not giving him any credibility at heavyweight yet, because I've not seen anything.

"Joshua is not worried about going in there with someone who's as big and strong as him, who is going to back him up and try to knock him out. If there's any concern there, he's more going to be concerned about this technical ability of Usyk and the fact that it might be a bit of a stand-off.

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"If it's going to be a technical duel, then that might be a concern, because Usyk is so technically good, so talented.

"But I think AJ will be thinking, 'I'll just use my size and strength, and after two rounds of a jabbing contest, then I'm going to close him down and step on him.'

"His trainer Rob McCracken will be telling him, 'Back this kid up, he's 6'3, he's not as big, not as heavy and as strong as you.'

"He can use his advantages and just squash him, get him out of there."

Usyk is hoping to emulate a small crop of fighters who have successfully packed on more size to challenge the champions in the top division, although Froch has raised doubts about whether Usyk can collect all of the world titles.

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"He's a top, top cruiserweight, but there's not many cruiserweights that step up and make that transition to heavyweight and do well," said Froch.

"David Haye was good at cruiserweight. He wasn't big enough.

"Evander Holyfield did it, but he had time to grow into the weight. If you want to go back as far as Michael Spinks 'The Jinx', who beat Larry Holmes twice after moving from light-heavyweight, you can go as far back as that.

"But there's not many, who step up from cruiser and really dominate. Holyfield is probably the best example."

Watch Usyk vs Chisora on Saturday, live on Sky Sports Box Office, from 6pm. Book it via your Sky remote or book it online here. Even if you aren't a Sky TV subscriber you can book and watch it here.