Former undisputed heavyweight champion Mike Tyson believes Francis Ngannou has a real "puncher's chance" of shocking the world in the upcoming fight against WBC champion Tyson Fury.

Ngannou, a former UFC champion, will make his pro boxing debut against Fury in a non-title fight, which takes place on October 28 in Saudi Arabia.

The MMA veteran hired Tyson to train him for the fight.

Tyson feels confident that Ngannou's feared punching power will translate over to MMA.

Fury has been able to overcome three fights with Deontay Wilder, who is widely regarded as one of the biggest one-punch hitters in combat sports. 

However, Tyson credits Ngannou with being the most dangerous puncher in Fury's path.

“Tyson Fury got dropped by a small guy early in his career,” Tyson said on The Jim Rowe Show. “[Francis] punches like God knows who, man. He’s an athlete, he moves quicker, works with his speed, and listen man, he only has to land one or two. Tyson’s never been in the ring with somebody that can punch this hard.”

As their training camp plays out, Tyson admits that he's been pleasantly surprised with Ngannou's progression in the ring.

“He asked me to go all out aggression,” Tyson said. “He’s moving his head, he’s getting it together, and he’s determined to do this stuff for his country, his people, his patriotic pride. This is really interesting. I’m very excited about doing this.”

Back in February of 1990, Tyson was shockingly knocked out by 42-1 underdog Buster Douglas. The outcome is regarded by most observers as the biggest upset in boxing history.

However, Tyson says a win by Ngannou would be an even bigger shocker.

“That would be a bigger upset than Douglas-Tyson,” said Tyson.