Former world heavyweight champion David Haye is backing KSI to overcome unbeaten Tommy Fury on October 14 in Manchester.
Earlier this year, Fury pulled off a minor upset when he picked up an eight round split decision win over Jake Paul, who suffered his first career defeat.
The younger brother of WBC heavyweight champion Tyson Fury has promised to batter and stop KSI when they step in the ring.
Fury is the first pro boxer that KSI will face. However, Fury is viewed by most observers as a young novice.
Most experts are siding with Fury to win the fight, because KSI is regarded as a social media star who crossed over to boxing to make crossover fights.
But, Haye believes otherwise and expects KSI to come over with the win.
"I think KSI will beat Tommy," Haye told Mirror Fighting. "I think Tommy will underestimate him, he will believe as he said throughout the whole campaign that he is not a real boxer but I think he's better than he's ever been before.
"I actually think the best of [KSI] still has yet to be seen, the last fight with the elbow that knocked out Joe Fournier there's not much you can take from that fight but I've been assured there's plenty more to come and it will be a massive, massive upset for boxing.
"He's going to embarrass a hell of a lot of people. Tommy's a massive favorite and people think he's the real fighter whose big brother is the heavyweight champ and he's doing it since he's a kid. He comes from a fighting family so for him to lose to someone considered a YouTuber in these fights that a lot of people don't give much credibility to, it will be pretty hard for him to bounce back."