Joseph Parker backs Andy Ruiz to put on a show against Anthony Joshua

Kiwi heavyweight boxer Joseph Parker is warning boxing fans and pundits not to write off American-Mexican boxer Andy Ruiz, ahead of his title fight against world champion and British fighter Anthony Joshua.

Ruiz is a heavy underdog in tomorrow's WBA, IBF, IBO and WBO heavyweight title bout against Joshua, which is set to go down in New York's famous arena – Madison Square Garden.

Parker fought Ruiz in 2016 and won by split decision to clinch the WBO heavyweight title.

The Kiwi heavyweight says Ruiz is a deceptively durable and slick fighter.

"A lot of people are underestimating him cause of his size and because of his physique," said Parker.

"I didn't underestimate him because I knew what he was going to bring when I fought him.

"So, I know he is going to be tough, he has all of Mexico behind him and he's going to be coming with a lot of heart."

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The Kiwi lost his WBO title to the Brit last year. Source: 1 NEWS

Joshua snatched the WBO heavyweight title from Parker in 2018, after defeating the Kiwi by unanimous decision.

"But it is a tough challenge fighting someone like Joshua, he's progressing each time and also he has faced many different styles," Parker said.

"He's [Joshua] brought good people into camp for sparring, it’s just going to be an exciting fight."

Parker says with Joshua's big frame, Ruiz has to take the fight to him and box him on the inside.

"It is the only fight Ruiz can fight [fighting on the inside], he can't box and move cause of the reach disadvantage that he has.

"So I think he has to get in close, that is the only way he will be able to throw combinations and his punches, get in close and be on his chest."

Parker today announced his signing with Eddie Hearn’s Matchroom Boxing and will face American fight Eric Molina on June 29 in Rhode Island.