Johnny Nelson, a former world champion, said that it would be difficult for Anthony Joshua beat Oleksandr Uzyk.
As he seeks to overthrow his Ukrainian opponent, the British heavyweight will be out for revenge in Jeddah next week.
After his devastating defeat last time, Joshua will be trying to beat Usyk.
Usyk is unbeaten in his professional career
From 1999 to 2005, Nelson was WBO's cruiserweight champion
AJ defeated Usyk on unanimous points last September. This was the latest loss for the 32-year old heavyweight champion.
He's determined to get his career on track with the big-money rematch live on Sky Sports.
Johnny Nelson, a former champion in cruiserweight, believes that the odds are against Joshua.
Sky Sports spoke to the 55-year old: "This isn't impossible, but it's hard."
"When he lost against [Andy] Ruiz, everybody said he was done, he's dead," but he said, "I have to change my tactics."
"This is what he has to do in this fight. He's got got to change his strategies. He attempted to beat Usyk at his game, but he did so by walking straight into Usyk’s plan. That's exactly what he wanted instead of using his natural abilities.
Anthony Joshua must fight for his cause to change this. Instead of following what worked in the past for him and what has gotten him to this point in his career, he out-smarted him.
Joshua was once lined up to clash with Tyson Fury or Deontay Wilder, but that was before the humiliating loss to Ruiz.
Nelson believes he is still working to rebuild his reputation.
He said: "Anthony Joshua had the crossover appeal when it comes to people who are interested in boxing and won't bat an eyelid at them."
"You look at his style and see what he did. There are always people who say, "Well this opponent wasn’t that." He wasn't given the credit that he deserved. This fight will be that fight.
"Remember, he has done it twice already. If Anthony Joshua beats him, the next person would be like, "Yeah, but Tyson Fury has not beaten you or Deontay Wilder."
"He will always have these things. But to me, this shows that you must respect him."
"Because, he's been in there with one the best fighters of the world and he was going to go in there beat him, if that happens where will the questions come?
People from all walks of boxing have made predictions about who will win the rematch in Saudi Arabia.
Frazer Clarke, a British boxer who was in the gym with AJ, believes he can "outhustle” Usyk this time.
Teddy Atlas, Mike Tyson's ex coach believes the Brit will lose not only to Usyk but Joe Joyce too. He could also face the winner.
