Andy Ruiz pulled off one of the most sensational boxing upsets by dethroning Anthony Joshua at New York's Madison Square Garden on Saturday.

Joshua was a huge favorite to retain his IBF, WBA, IBO and WBO heavyweight titles in the Brit's maiden professional fight overseas but was floored four times before being stopped in the seventh round.

Mexican banger Ruiz stunned Joshua, consigning him to a first defeat in one of the most famous boxing venues.

And one of Ruiz's biggest post-fight supporters is one of Joshua's countrymen, Tyson Fury.

Fury, who had a domestic verbal feud with Joshua for several years, was delighted for the big win by Ruiz.

"I was delighted for the smaller fat kid. Everybody has to go with the underdog. You see a big giant ripped in muscles and everyone expects the other guy to get knocked out in a round or two. I didn't because I knew how good Ruiz is," Fury said to CNN.

"I'm happy that he's a fat guy. We're both fat. He's an inspiration for all fat people out there. Everyone has always been told you need to be in shape, you need to be looking good, you need to have a great body. He's [Ruiz] just defied everything, the laws of ethics, because he came and he wasn't in great shape, he didn't look like a fighter and he knocked out this guy [who] looked like an Adonis.

"Styles do make fights and if he [Joshua] could have done anything he'd have done it there and then that other night. AJ didn't just get knocked out fluky, he got beaten up first and then knocked out."