Johnny Nelson believes Anthony Joshua's boxing career would lose all credibility if he is beaten by Francis Ngannou next month.
Former WBO cruiserweight champion Nelson has criticised Joshua's decision to accept the fight, claiming it lacks 'common sense'.
Former MMA star Ngannou will step into the ring for his second professional boxing fight in Riyadh, Saudi Arabia on March 8.
The Cameroon-born fighter gave Tyson Fury a major scare on debut last October, almost pulling off one of the biggest upsets in the sport's history.
Anthony Joshua has been warned his fight against Francis Ngannou is a huge risk
Getty
After losing back-to-back fights against Oleksandr Usyk, Joshua has won his last three bouts since April 2023.
He wants to fight the winner of Usyk vs Tyson Fury, which has been postponed until May 18.
Nelson believes Joshua will win against Ngannou, telling Sky Sports News: "I think he comes through it with flying colours.
"I think Joshua wants to be world champion again, I think Joshua knows what responsibility he will have.
"He will know 'I just have to get through this fight and get the win' because of the big pot of gold at the end of it."
However, Nelson believes the risk of taking on the fight against Ngannou far outweighs the reward.
The pundit, who remains the longest reigning cruiserweight champion of all time, says Joshua's career would be 'in tatters' if he loses.
Nelson added: "Common sense is risk-reward. For me, the risk way outweighs the reward. If Joshua somehow loses to Ngannou, that is it - credibility is gone, career is in tatters, and it is a lot of rebuilding.
"How is he ever going to get his head around losing to Ngannou? The risk is far too high, why would you?
"You've got no excuse to lose to this guy. He's had one professional boxing match.
"If you lose to him, all the Olympics, all the success, being two-time heavyweight champion, it is all gone, it has gone up in smoke because that is what you remember, you lost to a guy who had one previous fight before you.
"The risk far outweighs the reward. To me, common sense, I wouldn't do it.
"Business-wise, I wouldn't do it, but Ngannou has got himself into a position where you cannot ignore him."
LATEST SPORTS NEWS:
Johnny Nelson says Anthony Joshua's fight with Francis Ngannou lacks common sense
Sky Sports
Former unified champion Joshua lost his belts in his first fight against Usyk in September 2021.
Nelson says the 34-year-old has got to a point in his career where he now cannot afford to lose.
He said: "It has got to be just for him as an individual. It is hard to swallow when you, all of a sudden, realise you are not the best fighter in the world, but you want to be the best fighter in the world.
"The great side of our sport is the glow, and the downside is when everybody wants to be your boss and tell you how bad you do.
Anthony Joshua and Francis Ngannou will fight on March 8 in Saudi Arabia
Getty
"Joshua, he needs to get these wins, the pride he has. To possibly lose to Ngannou, how would he be able to lift himself mentally, never mind how the press will crucify him?
"So, he understands what he has got to do - and I suppose we all do."