It wasn’t a fluke.

That’s Andy Ruiz Jr.’s mantra now that he and Anthony Joshua are busy promoting their heavyweight championship rematch. The new IBF/IBO/WBA/WBO champion can’t wait until he gets his opportunity to prove it December 7, when Ruiz and Joshua are set to fight again in Diriyah, Saudi Arabia.

Ruiz keeps hearing and reading how he is more focused on continuing to celebrate his life-altering upset of Joshua than preparing for their immediate rematch. He assured Joshua and promoter Eddie Hearn during a press conference Wednesday in Saudi Arabia that he is fully focused on successfully defending those titles in three months.

“I’m really hungry,” Ruiz said. “A lot of people are saying that I’m not training, that I’m not taking it serious. But come on – I’ve got all these belts. Like [Joshua] said, there’s a lot of responsibilities to this. But I’m gonna try my best, and God knows I’m gonna try my best, I’m gonna keep these belts, and I’m gonna have ‘em back in Mexico. But I’m really excited, man. December 7th, I’m gonna make [more] history and I’m gonna win here in the same fashion, the same way that I won June 1st. And I’m gonna prove everybody wrong.”

The 30-year-old Ruiz proved virtually everybody wrong June 1 at Madison Square Garden in New York.

England’s Joshua (22-1, 21 KOs) was more than a 20-1 favorite the week of their bout, but the resilient Ruiz got up from a third-round knockdown, quickly changed the complexion of their scheduled 12-round fight and pulled off one of the biggest upsets in boxing history.

Ruiz (33-1, 22 KOs), of Imperial, California, came back to drop Joshua twice in the third round and twice in the seventh. Referee Michael Griffin called an end to their fight at 1:27 of the seventh round, when Joshua, dazed and bleeding from his nose, ignored Griffin’s command to walk forward from his corner.

The three-day, three-country press junket to promote Ruiz-Joshua II is set to continue Thursday in New York. It’s scheduled to conclude Friday in London.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.