Tommy Fury's uncle claimed boxing was full of "vomit c***" - just minutes after his nephew's huge fight with Jake Paul was announced.
Tommy will take on YouTuber Paul in a pay-per-view bout in Tampa, Florida on December 18 after months of speculation.
Shortly after the fight was confirmed, Peter Fury tweeted: "Happy I’m not any part of the total vomit c*** I see and hear in boxing today.
"Only few gladiator spirits left in this game. Rest full of frauds! Just my opinion. Great weekend to the real souls."
Peter is known for training two-time heavyweight world champion Tyson Fury and is the father of fellow boxing star Hughie Fury.
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Tyson has previously said: "If I wasn’t with Peter, I wouldn’t be in boxing. I wouldn’t train with anyone else."
Paul announced his fight with Tommy on Friday evening and, as expected, mocked the Love Island favourite by calling him "Tommy Fumbles".
Tommy has agreed to change his name to the aforementioned if he loses to the YouTuber.
Defeat would effectively end the Brit's boxing career due to his opponent's background. Tommy's professional record is 7-0.
Paul said: "It's finally official. Timothy had no choice but to sign the contract so he could finally pay his bar tabs, afford a shirt for the club, and stop living off Molly!
"December 18 in Tampa Bay, I'm changing this w*****'s name to Tommy Fumbles and celebrating with Tom Brady. Pucker up Timmy... it's time to kiss your last name and your family's boxing legacy goodbye."
Although Peter didn't explicitly refer to Tommy's upcoming fight, boxing fans on social media assumed that was the case and many agreed with his comments.
Others, though, have defended the fight. One boxing fan wrote: "I don't see anything wrong with Paul vs Fury. If he [Tommy] wins, he can carry on from where he was."
Tommy, meanwhile, has promised to teach Paul a boxing lesson. He said: "Jake Paul is about to learn a serious life lesson. This is my world and he doesn't belong here.
I'm not one of these MMA men or basketball players. I have been boxing my whole life. I will show the world the difference between a YouTuber and a real fighting man."
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Once Paul vs Fury is settled, the YouTuber wants to take on KSI in the ring. Paul said: "I think KSI should retire from everything he's doing.
"[He has] Seven million monthly listeners, that means he makes $30,000 a month from Spotify. That's $360,000 a year, versus fighting me for $5m.
"You can see why he's scared... we may as well make that fight happen. After I beat Tommy he'll be the only guy from the UK left."
