Jake Paul has told John Fury having a son who became heavyweight champion is the only accomplishment of his life.
John's son Tyson is a two-time heavyweight champion who currently holds the WBC and The Ring titles.
YouTube star Paul was scheduled to take on Tommy Fury - the youngest son of John's - next weekend, but the Brit pulled out of the fight on Monday with a broken rib and bacterial infection.
Paul will now rematch former UFC champion Tyron Woodley - who he outpointed in August - on the December 18 card in Tampa, Florida.
John and Paul traded words at a pre-fight press conference last month with John stating his son would "f***" Paul's girlfriend "like a dog" after the fight.
'Gypsy John' was a former boxer who retired with a record of 8-4, being knocked out by Steve Gerber and future world title challenger Henry Akinwande in his last two fights.
And Paul has labelled John a "cringe old man" whilst also taking aim at his boxing career.
“I would say, start looking for a new job. You are a cringe old man, he’s an old, miserable man who never accomplished anything in his life," he told talkSPORT.
“He has a mediocre boxing record and the best thing he ever did was have sex with Tyson’s mum to spawn Tyson. That’s his only accomplishment – having a giant kid who became heavyweight champion of the world.”
John - who is hopeful Paul will fight Tommy next spring - said his son is "coping well" with the bacterial infection and a training partner was "responsible" for his broken ribs.
Fury said he was "heartbroken" after withdrawing and outlined his hopes of rescheduling a fight with Paul once fully recovered.
Will it be repeat or revenge in the rematch between Paul and Woodley? Let us know your prediction in the comments section below
But Paul has vowed to make his rival Fury wait "years" to reschedule his "fumbled" opportunity at a fight.
The 24-year-old also claimed he would fight both John and Tyson, but only if the heavyweight champion was to make the five stone drop down to reach the cruiserweight limit.
“I would fight John Fury, for sure! I think it would be hilarious. I was hoping he would have punched the TV," Paul continued.
“If he would have done it, man that would have been the most legendary press conference moments ever. He’s kind of a p***y for not.
“I would fight him. I would fight the whole family. If Tyson moved down to cruiserweight I would fight Tyson no problem.”
