Novak Djokovic has withdrawn from next week’s Qatar Open to place a further doubt on his participation in the Australian Open. The Serbian has been sidelined for the past six months and was unable to play in an exhibition match in Abu Dhabi on Friday when an elbow injury flared up.

On his website he said: “Unfortunately, the situation with the elbow has not changed for the better since yesterday. I still feel the pain. Therefore, I will have to withdraw from the ATP tournament in Doha.”

Djokovic added: “After thorough consultations with the medical team, we decided to keep up with the therapies and elbow treatments.

“Only when I’m 100% ready to play, will I be able to come back. I hope it will be soon. I want to thank everyone for their patience and understanding.”

Djokovic has not played a competitive match since Wimbledon and had been due to face Roberto Bautista Agut on Friday.

Andy Murray – who has also been out of action since Wimbledon – stepped in to replace him for the one-set match.

Roger Federer is already in Australia for the Hopman Cup and dismissed Japan’s Yuichi Sugita 6-4 6-3 in just over an hour on Saturday to give Switzerland a winning start in the competition and send out a signal to his opponents at Melbourne Park next month.

Coming off a fruitful year that yielded two grand slam titles, the world No2 looked fit and sharp. Federer hurried to save a break point in his first game but otherwise did not have any trouble against the 29-year-old Sugita, whom he broke in the fifth game, and there was no looking back from there.

Belinda Bendic beat Naomi Osaka 7-5 6-3 in the women’s contest to clinch Switzerland’s victory in the round-robin stage of the mixed team event.

CoCo Vandeweghe beat Anastasia Pavlyuchenkova and Jack Sock defeated Karen Khachanov to help United States beat Russia at the Perth Arena.