Britain's 'Juggernaut' was training alongside Ruiz in America and didn't believe he would win heavyweight belts based on what he saw

Joe Joyce has exclusively told talkSPORT a surprising story about Andy Ruiz Jr’s sparring and training preparations, following his upset win over Anthony Joshua.

The Mexican-American heavyweight stunned the boxing world by knocking AJ out on June 1 at MSG with Joyce more shocked than most.

Getty 2 Joe Joyce will face Bryant Jennings on July 13 at the O2 Arena

Britain’s ‘Juggernaut’ has spent plenty of time working with AJ as part of the Team GB amateur setup in the past and also witnessed Ruiz sparring at his old training camp in America.

From his experiences with both men, he quickly made his mind up about who would win.

Joyce explained on the talkSPORT Sports Breakfast: “I thought he [Joshua] would dispatch him quite easily because Ruiz was up in Big Bear [California] where I was training with Abel Sanchez.

“He was sparring with Charles Martin who Joshua flattened to get his first world title.

getty 2 Andy Ruiz Jr is now the unified heavyweight champion

“I didn’t really think too much of Ruiz and he didn’t want to spar me!

“I don’t think his fitness was there because he could only do roughly two rounds with Charles Martin! And he didn’t want to spar me.

“I didn’t really think he could do it.”

LATEST BOXING NEWS FORCE Eddie Hearn reveals 'bad intentions' text Joshua sent him about what he'll do to Fury fight World Boxing Super Series: Date and time, how to watch, live stream and undercard FIGHT NIGHT Josh Taylor fight: Start time, live stream and undercard for Khongsong clash FAMILY Tyson Fury and Tommy Fury have another brother who's now set to become pro boxer DROP THE BELT Oleksandr Usyk's co-promoter expects Anthony Joshua to vacate WBO world title OPINIONS Anthony Joshua vs Tyson Fury: Hearn and Warren each explain why their man will win RAW POWER Watch as boxer is knocked unconscious before hitting the canvas in first round EXCITING Hearn reveals he'd be 'all in' for a boxing game as he discusses 2K relationship EERIE Eddie Hearn details 'unique, bizarre experience' moments after Dillian Whyte was KOd crossover Anthony Joshua to feature in FIFA 21 wearing clothes designed by Hector Bellerin

Andy Ruiz Jr parades heavyweight titles won in Anthony Joshua fight in hometown Imperial

As it happened, Ruiz got up from a third round knockdown to floor Joshua four times and cause the seventh-round stoppage.

There have since been multiple conspiracy theories suggesting ‘explanations’ for the result, and Joyce admits that he doesn’t quite know what to make of it all.

“I saw his fast hand speed on the pads and stuff, but I was very shocked that night.

“I thought maybe Joshua was out of the ring for too long and he was a bit rusty.

“Or the New York crowd got to him, I don’t know what happened.”