Andy Ruiz Jnr

Joshua-Ruiz 'can change boxing'

Joshua lost his WBA, WBO and IBF belts to Ruiz in a stunning upset at Madison Square Garden in June.

Matchroom Boxing last week confirmed a rematch for December 7 in Riyadh, with Ruiz having refused to fight in Britain.

The Mexican-American is yet to comment on the scheduled fight, but Matchroom promoter Hearn told a news conference on Monday: "Both fighters signed for this fight. The governing bodies have been informed."

Ruiz vows to win rematch as Joshua is 'not good at boxing'

Ruiz was sensationally crowned IBF, WBA and WBO world heavyweight champion by stopping Joshua at Madison Square Garden at the start of this month.

The Mexican is set to face Joshua in a rematch later this year and says the 2012 Olympic champion does not have the skills to reclaim his belts.

Ruiz said: "The rematch is going to be the same. I am going to be more prepared and more ready.

"I know his flaws. I can do a lot better. The only thing that he can do is just run around, he's not good at boxing."