Stefanos Tsitsipas has labelled Novak Djokovic the GOAT of tennis after losing the Australian Open final in three sets at Melbourne Park.

By winning the first Grand Slam crown of the season, Djokovic also took the world No.1 spot as the debate over who is the best tennis player of all time continued.

Rafael Nadal has also won 22 Grand Slam crowns including 14 French Open titles and will look to make it 15 victories at Roland Garros in May. However, the 36-year-old needs to recover from a hip injury which contributed to him crashing out of the Australian Open at the second round stage this month.

Roger Federer is also in the GOAT debate having won 20 Grand Slam titles and spent 310 weeks as world No.1 during his career which ended last year.

Tsitsipas has lost two major finals to Djokovic and overlooked Nadal and Federer in naming the Serbian as tennis' GOAT.

"It speaks for itself, the numbers," said world No.3 Tsitsipas in his runners-up speech after losing the Australian Open final 4-6-4, 6-7(4), 6-7(5).

"I've had the privilege to play a lot of high intensity matches. But he's one of the greatest in sport and the greatest who has ever held a tennis racket, for sure. It's been an unbelievable journey for you, I admire what you've done for sport and you make me a better player, so thank you."

With Nadal aged 36 and Djokovic a year younger it remains unknown how long either star has left on their incredible careers before retiring.

However, Djokovic's coach Goran Ivanisevic believes his star can compete for tennis' major honours for years to come with Margaret Court's all-time record tally of 24 major titles within his grasp.

Ivanisevic was asked how long he feels Djokovic can continue competing at the top.

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The coach replied: "Definitely two, three more years. The way he's taking care of his body, the way he approach about everything, the food, it's amazing. It's unbelievable the level.

"We talking about young guys. They're here, it's great for tennis, great for the future of tennis. But you still have these two guys battling. This was Novak home court, and now we going next one to Rafa home court in this handball match of 22-22."