Nadal ended his 2017 season two matches early, pulling out midway through the ATP World Tour Finals in London, citing a right knee problem.

The Spaniard was due to make his comeback just a month later at the Mubadala World Tennis Championship last week but was forced to withdraw before also confirming he would not play at the Brisbane International.

However, he flew to Australia yesterday and was today spotted working on the Rod Laver Arena court, the venue for the Australian Open.

“Already in Melbourne! Practiced today @RodLaverArena and also excited for the @tiebreaktens coming up on Wednesday 10th!” Nadal said on Twitter, referencing the exhibition event in which he and Djokovic are both due to take part next week.

But Djokovic too is battling an injury, having pulled out of the same Abu Dhabi tournament last week and cancelling his scheduled appearance in Doha for the Qatar Open.

The Serbian has been out for a considerably longer period than Nadal, having retired from his Wimbledon quarter-final against Tomas Berdych in July and not played competitively since having elbow surgery to repair a long-term problem.

However, tennis player Stephen Kaldawi revealed that Djokovic had also been in action on Rod Laver today with an Instagram picture featuring the two of them.

“Solid session on Rod Laver with one of the best @djokernole #ausopen2018,” Kaldawi captioned the photo.

Djokovic has already revealed that he will use two exhibition events in the week leading up to the Australian Open as dry runs for the first Grand Slam of the year.

“After pulling out from Abu Dhabi and ATP Doha events due to pain in his right elbow, Novak is travelling to Australia where he will take part in two exhibition tournaments,” said a statement on Djokovic's website.

“After the two events, a decision will be made about his participation at the first Grand Slam of the season, the Australian Open, where Novak has been crowned champion six times.”