Rafael Nadal will again sit out the ATP Cup in Melbourne on Friday with a back injury which has cast a shadow over his hopes of a record-setting 21st Grand Slam title at the Australian Open.

The world No 2 missed Spain’s opening clash with Australia on Tuesday and the 34-year-old was also absent when the schedule was released for Friday’s tie against Greece.

“I’m not well enough to play. I’m improving bit by bit, but I’m not ready to play a match with maximum intensity,” Nadal told Spanish broadcaster Vamos.

Nadal hasn’t played a competitive match since the semi-finals of the ATP Finals in London on November 21. His only appearance since was an exhibition match against Dominic Thiem in Adelaide on Friday.

Nadal had an extra day to recuperate on Thursday after all matches in the warm-up events for the Australian Open were postponed after a Covid-19 case at a tournament hotel.

However, Pablo Carreno Busta and Roberto Bautista Agut will lead Spain’s challenge against Greece on Friday.

The Australian Open gets underway on Monday with Nadal, the 2009 champion, looking to edge ahead of Roger Federer who also has 20 Slam titles to his name.

Federer is not playing in the tournament and will only return to the tour in Doha in March.