Carlos Alcaraz says the challenge of toppling 10-time champion Novak Djokovic at the Australian Open gives him "extra motivation" as he aims to end the Serbian's long reign in Melbourne.

The Spanish world number two missed the Grand Slam last year with a leg injury but is seeded to meet Djokovic in the final in Melbourne.

The pair have met five times –- all in semi-finals or finals -– with the veteran leading 3-2.

Djokovic, 36, is unbeaten at the year's opening major since 2018 but Alcaraz, who came out on top in a thrilling Wimbledon final last year, said that only increased his desire to win.

"It's an extra motivation for me," the two-time Grand Slam champion said on Saturday. "I'm an ambitious guy.

"I always want to play against the best players in the world to see what my level is. Obviously it's a good test, playing against him in the places or in the tournament that he's almost unbeaten.

"Yeah, I am looking to reach the final and hopefully playing a final against him. It would be great, obviously."

Alcaraz is aiming to become just the fourth man to win three majors before turning 21 after Rafael Nadal, Bjorn Borg and Mats Wilander.

The 20-year-old chose not play a warm-up tournament before the Australian Open, which starts on Sunday, saying he had to recharge his body and mind.

"We discussed with my team, as well, that we need almost four, five weeks of pre-season to prepare well this season, for the first Grand Slam of the year," he said.

"We have no time if I wanted to play a tournament before the Australian Open. In the end we preferred to come here to the Australian Open, straight to a Grand Slam. I think I'm a guy who doesn't need so much competition before a big tournament."

The Spaniard is in Melbourne without his coach Juan Carlos Ferrero, who has had knee surgery. Instead he will be coached by Samuel Lopez, who worked with former world number one Ferrero during his playing career.

Alcaraz admitted losing Ferrero was a blow but said he trusted Lopez.

"I believe in him, Juan Carlos, as well," he said of Lopez. "I think I can learn a lot from him as well. Let's see how is going to be. As I said, I trust him 100 percent."