IBF, IBO, WBA, WBO heavyweight world champion Andy Ruiz believes Anthony Joshua is worried about their upcoming rematch in Saudi Arabia on December 7.

Back in June, Ruiz shocked the sport when he dropped Joshua four times to secure a seventh round knockout to capture the unified crown at Madison Square Garden in New York City.

I think right now he's pressured, he's more focused on getting the belts back,” Ruiz told iFL TV.

"I think he's worried about getting the belts back. But I think he's in it to win it. He wouldn't have picked this fight for nothing. Hopefully he brings it December 7 because I'm going to do whatever it takes to retain those belts and bring them back over here."

WBC heavyweight champion Deontay Wilder will be very interested party.

Should he overcome his rematch with Luis Ortiz this coming Saturday night at the MGM Grand in Las Vegas, he would like to face the winner - although he admits a Joshua fight is less likely.

“With Joshua, we tried many times to get that fight unfold and make a dream fight happen, you know for the fans to unify the division,” Wilder said.

"To have one champion, one face, one name. As you can see that was a long process, a process where we had different markers being stretched.

“Once we completed, we had to do something else, we had to do this, we had to do that. It was a lot. This is a gladiator’s sport, this is a man’s sport and I’m a grown man and I don’t have time for games. Being that Ruiz is under the same stable as I, a much easier fight to make, and I think an even more exciting fight as well.”