Ruiz Jr v Joshua 2: Anthony Joshua believes Andy Ruiz Jr is the best fighter on the planet right now

Ruiz, who was born in America but fights for Mexico, caused a major shock in June when he handed out a first defeat for Joshua to win the WBA, IBF, WBO and IBO world titles in New York.

In the third part of the trilogy of press conferences to promote the rematch in Saudi Arabia, Joshua said: "My fights are the elite of the elite and are top of the crop. That little bit of motivation of fighting someone who has the skill set and is the champion.

"It's not like I'm fighting someone as a stepping stone to a champion. We can't overlook Andy and his talent and his success in the ring as I'm fighting the best out there right now. In my opinion Andy Ruiz is the best heavyweight out there.

"I respect Andy and his team. I'm happy for him. I know what it means to fight for the championship and win the championship so he's given hope to the people of Mexico."

Former Olympic champion Joshua was knocked down four times by Ruiz before he was stopped in the seventh round on his US debut this summer, marking one of the biggest upsets in heavyweight history.

But he says his motivation to return to the top is a big factor ahead of the December rematch.

He added: "Once I've got my purpose of life organised, I can do anything and that motivation will be the same.

"Put me on the street to clean graffiti off the wall, I want to make sure my graffiti cleaning is better than yours - and that's just my purpose in life.

"So motivation isn't just about boxing. I've got to make a few changes in my lifestyle now to correct and align them again so I align my stars.

"So, come December 7 I'm shooting straight and I know where I'm heading - and that's towards those titles that at the minute are just out of reach, but sooner or later I'll be able to touch them again."

The fight, the latest high-profile boxing event to be held in Saudi Arabia after Amir Khan's victory over Australian Billy Dib in July, will take place in Diriyah, a town on the outskirts of the capital Riyadh.

Ruiz is pleased he proved his doubters wrong last time out and hopes for more of the same in the second encounter.

He said: "Everybody doubted me since I was a little kid and there's times that I wanted to quit, but having the right people around me, telling me to keep pursuing, saying 'you're going to be champion', even when I didn't believe it when I was younger. I just keep pursuing.

"The main thing is believing and doing something you love. I've been doing this since I was six years old. This is the only thing I know how to do besides working with my dad in construction and being in the sun and I don't want that. That's why I have to give it all I've got.

"I just have the mindset that I would become the first Mexican heavyweight champion of the world and I'd been praying to God and, what do you know, that came true in June.

"I'm ready for December 7, AJ wants to get these belts back but they're mine. We're going to win in the same fashion. We're going to start training somewhere and we're really excited about this fight."

Related Boxing links

• Joshua v Ruiz: First fight report & highlights
• Watch: Joshua's in-depth analysis of defeat to Ruiz Jr
• Ruiz v Joshua II: Sky Bet's big-fight odds
• More Boxing news