Usyk vs Witherspoon: Deontay Wilder issues damning verdict on Oleksandr Usyk’s heavyweight ambitions

Deontay Wilder has derided Oleksandr Usyk as "too small" to become a world heavyweight champion.

Usyk debuts in the top division tonight at 2am against Chazz Witherspoon, live on Sky Sports Action, before targeting heavyweight honours to add to the undisputed cruiserweight title that he captured.

"He's not a threat to me," WBC champion Wilder exclusively told Sky Sports. "He's too small for me. He does a lot of movement but that doesn't faze me."

Book Taylor-Prograis and Chisora-Price

Live Fight Night International

Wilder is four inches taller than Usyk with a five-inch reach advantage. They are unbeaten in a combined 58 pro fights.

Usyk will retain his status as the mandatory challenger to the WBO heavyweight title if he extends his unbeaten record to 17-0 in Chicago tonight. That title will be defended by Andy Ruiz Jr against Anthony Joshua on December 7, live on Sky Sports Box Office, and Usyk will expect to fight for the belt next year.

Tony Bellew, who was beaten by Usyk last year, believes his former rival's best chance at winning a heavyweight title would come against Wilder.

"Wilder, and that's an easy answer," Bellew said. "Don't get me wrong, if Wilder lands on him then it's not going to end well for Usyk, but you can say that about any heavyweight who Wilder lands on.

"I just think [Joshua and Tyson Fury] are too big for him. Fundamentally, he's a much better boxer than all of them, and I include Fury in that, but he's just too small to compete with them for 12 rounds. I think the size of Fury and Joshua would be a massive advantage and I don't think Usyk could overcome it.

"If he was to fight Andy Ruiz tomorrow, then I think he'd win that fight by just being himself and doing what he does best. There are only a few guys I don't see him winning against, but he's by far the most skilled fighter in the division and that will always give him a chance."

Wilder first defends his WBC crown against Luis Ortiz on November 23 and plans a second fight with Fury in 2020.

When asked who his biggest threat is, Wilder told Sky Sports: "Myself. I have something that I've been blessed with. It lasts from the first to the 12th - it never goes away.

"People may think I'm fatigued or out of it but, if you get hit, there are repercussions to be paid. It's amazing because I don't even know the strength of my own power.

"I hold my fiancee's hand and she says: 'Baby, you're squeezing me too tight'. I am very heavy handed.

"I'm only getting better with my technique. One thing, out of everything, that I've been working on is my technique. From point A to point B with speed.

"The speed is the power but I already have the power. So when all that comes together, when lightning and power transfers from point A to point B? Bam, baby. Goodnight."