Francis Ngannou is guaranteeing Tyson Fury will "hit the canvas" in their upcoming fight ... telling TMZ Sports that one of his punches will send the heavyweight champ crashing to the ground.
The former UFC star made the proclamation while outside LAX this week ... two months before he steps into the ring against the undefeated Fury (33-0) in Saudi Arabia.
While he stopped short of ensuring it will be a KO -- he told us it wouldn't shock him if that ends up being the case.