By Keith Idec

David Haye is one of only two boxers that can offer a personal perspective on what it takes for a cruiserweight champion to move up and beat a huge heavyweight champion.

The retired Haye’s advice to Oleksandr Usyk would be to tighten up his defense. The former heavyweight and cruiserweight champ didn’t consider defense an issue for Usyk until he watched Tony Bellew regularly land his right hand against the unbeaten Ukrainian on Saturday night in Manchester, England.

The 6-feet-3 Usyk took Bellew’s best shots well, but that might not hold true if bigger, stronger heavyweights like Anthony Joshua or Deontay Wilder hit him as flush as Bellew was able to do at times. Bellew was effective enough to have the lead on two scorecards when their scheduled 12-round bout was stopped in the eighth round, but Bellew didn’t appear to hurt Usyk badly with any of those punches.

Though Bellew hit Usyk more than Haye anticipated, Haye is looking forward to assessing how the IBF, WBA, WBC and WBO cruiserweight champion performs once he moves up to heavyweight. Ukraine’s Usyk (16-0, 12 KOs) is expected to make his heavyweight debut in his next fight.

“He has the skill,” Haye told BoxingScene.com following Usyk’s eighth-round knockout of Bellew at Manchester Arena. “He showed tonight he’s got the skill. But the shots he was taking tonight against Bellew, you don’t wanna be taking those shots from a Joshua or a Deontay Wilder. You know, his defense wasn’t as slick as I thought it was going into this fight. He was getting counter-punched, he was getting hit at range. He needs to do a lot of work. He could physically do it. It is possible, because I’ve done it, Evander Holyfield’s done it.

“We are the only two fighters in history to have moved up from cruiserweight, as a champion, to heavyweight and won world titles. So, for me, it’s a tough ask, particularly with the modern-day heavyweight being so big, being so explosive, and being so young and in their prime. It’s not like [Joshua] is an old guy [29]. It’s not like it’s a John Ruiz with a title. Maybe he could beat that type of guy. But someone like Deontay Wilder, someone like even Tyson Fury, you’re gonna need to do something very spectacular.”

The 6-feet-3 Haye weighed in at just 217 pounds when he edged Russian giant Nikolay Valuev by majority decision to win a piece of the WBA heavyweight championship in November 2009. The 7-feet Valuev weighed in at 316 pounds, 99 more than Haye, for that 12-round fight in Nuremberg, Germany.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.