George Groves has delivered a damning indictment of the YouTube boxing craze, claiming it makes his "skin crawl".
Following KSI's win over Logan Paul in their rematch last year, the younger Paul brother, Jake, took on AnEsonGib in Miami last week.
All four fighters were granted professional licenses despite having no experience in the ring beyond a handful of white collar bouts.
The fad looks set to continue with Logan Paul in talks to fight NFL star Antonio Brown and Jake Paul calling for a fight with KSI.
But former world champion Groves believes the fights are an insult the sport.
"It's horrific, it's abysmal," he said on After The Bell, in association with Betfair. "It makes my skin crawl.
"I could get on board with the entertainment value but why is it called professional boxing? It's so demeaning; how do you distinguish between Logan Paul and Demetrius Andrade, they're both professional boxers.
"KSI against Logan Paul was billed as a laugh and a one-off but everyone knew it wouldn't be and where does it now end? That fight at the weekend was a complete joke.
"What are we watching? There are not enough talented YouTubers to full a league or whatever they want to set up.
"I remember watching Ricky Gervais have a white-collar fight and that's where it is, that's entertainment.
"Even if you want to put them on a pro show, great, but don't call them professional boxers. It's scary because people soon won't be able to tell the difference.
"I don't find any of it genuine. I've never been a fan of wrestling and this is on par with that, none of it is real."
