KSI has boldly claimed he could defeat Floyd Mayweather, and even said his old rival Logan Paul could get the better of Mike Tyson.
KSI beat Logan Paul in YouTuber boxing's breakthrough moment but they came together to discuss sharing the ring with legends.
The 28-year-old boasted on the Impaulsive podcast: "I'd [beat] up Mayweather."
Logan Paul replied: "It's funny you said you could beat him. I wanted to ask you about this - you probably think you could beat most people?"
KSI: "I feel like that's the mentality you have to have."
Logan Paul: "But then people laugh at you, it'll be headlines."
KSI: "People will be like: 'What? KSI thinks he could beat Mayweather? Shut up.'
"And then it's like: 'Alright, cool, let's go then.'
"Then it happens and everyone's like: 'Oh damn.'"
Logan Paul went the eight-round distance in an exhibition bout with Mayweather, who is now 44, earlier this summer.
His fellow online influencer Joe Weller about that bout: "Looking at the internet. The majority of my Twitter are saying, 'Logan Paul just beat Floyd Mayweather'.
"I was expecting Floyd to just end it soon. Make a statement saying that: 'Boxing is not a game. You YouTubers get out of it.' The fact that Logan Paul got to the end, fair play, proper respect.
"I think Logan Paul won. If there was a winner, I think Logan Paul won."
KSI then said to Logan Paul: "I think you could beat (Mike) Tyson.
"You've got to remember, this isn't Tyson who's 18, this is Tyson who's .
"People don't understand, we train like boxers."
Tyson returned to the ring for an exhibition match against fellow legend Roy Jones Jr last year.