Tyson Fury said he could beat Oleksandr Usyk with no training and after "sinking 15 pints of Peroni" the night before in a news conference on Wednesday ahead of their title fight next month.
WBC champion Fury and Usyk, who holds the IBF, WBA and WBO straps, will fight for the undisputed heavyweight championship on May 18 in Riyadh, Saudi Arabia.
While Fury praised Usyk (21-0, 14 KOs) as a great champion at cruiserweight level, he said the step up will prove too much when they clash in just over a month's time.
"I think if I didn't train at all for this camp and came in at 25 stone and sank 15 pints of Peroni beforehand, then the next day go in there ... what's he going to do? Jib and jab me around?" Fury said at the news conference in Morecambe, England.
"Take nothing away from him, but he couldn't do anything with Derek Chisora, it was a 50-50 fight."
The bout was originally set for Feb. 17 in Riyadh, Saudi Arabia, but was postponed after Fury suffered a cut in sparring earlier in the month.
Fury (34-0-1, 24 KOs), who is known for his entertaining interviews and hurling insults at opponents, was full of respect for Usyk on Wednesday, but he warned he expects to win in emphatic fashion in May.
"It's not personal, it's strictly business for both fighters," Fury said. "There's a lot of stuff on the line, but I don't hate him and he don't hate me. I respect him as a man, as a fighter, he's undisputed cruiserweight champ, he's undefeated heavyweight champion. Anyone would have to respect the man's achievements.
"[But] we have weight divisions for a reason. When the cruiserweights step up to the big boys, they get found wanting."
The Fury camp also revealed how they will target Usyk, believing he has a weakness when it comes to taking shots to the body.
"I've looked at a lot of his fights, going back to his amateur days, and he is a bit of a crybaby when it comes to getting hit in the body," Fury's promoter Frank Warren said. "He cries to the referee a lot. He doesn't like it. For me, the biggest exponent of exploiting a fighter's weakness is the professor here [Fury]."
Turki Alalshikh, chairman of Saudi Arabia's general entertainment authority, has said either fighter will have to pay $10 million from his purse if they pull out of the bout.
Fury needed 11 stitches after he was hit with an elbow above his right eye in February, but he said he has had a great camp leading up to the rearranged date.
"I'm training hard, obviously, in fantastic shape, obviously. There's no room for error, no room for not training right," Fury said.
"I actually am having a fantastic training camp. No complaints, working very hard, got me dad in camp this time, so got my secret weapon as well. Can't do any more really."