Joe Joyce was as shocked as anyone, when he saw Andy Ruiz put away Anthony Joshua in seven rounds on June 1 at Madison Square Garden in New York City.

Joshua went down four times, before the contest was waved off in the seventh round by the referee.

Ruiz was a massive underdog and very few, if anyone, gave him a shot to win. Most observers predicted Joshua would win by knockout in the first six rounds.

Joyce and Ruiz were stablemates for a brief period - when both boxers were being trained by Abel Sanchez in Big Bear, California.

During their stint together, Joyce would have never expected Ruiz to one day topple Joshua for the WBO, IBO, WBA and IBF world heavyweight titles.

 “Not in a million years. I saw Andy Ruiz in Big Bear and he was sparring with Charles Martin. But he was struggling to do two to four rounds and he didn’t want to spar me. I was just thinking it would be a walkover job for Joshua. Little did I know,” Joyce told Boxing News.

“I did a load more rounds with Martin. I think [Ruiz] was struggling with fitness, struggled with altitude and he wasn’t willing to spar me. I didn’t think Ruiz was that powerful a puncher,” Joyce said. “He must have really pulled out all the stops training for that fight."

If anything, Joyce believes the contest was a clear exposure of Joshua's chin.

Before suffering his first loss, Joshua had been dropped by Wladimir Klitschko, and he was rattled by Dillian Whyte and Alexander Povetkin.

“To see [Ruiz] be so calm under fire and counter, he’s really fast and came in low with quick shots. It startled Joshua. I think it shows how Joshua hasn’t really got a good chin. Once he gets hit he seems to be in trouble. Imagine him against Wilder… When he fought [Wladimir] Klitschko he was troubled but Klitschko didn’t have it to finish him off but Ruiz definitely did. I guess that was the difference," Joyce said.