Defending champion Novak Djokovic of Serbia survived a marathon match in the Australian Open Round of 16, beating Switzerland's Stanislas Wawrinka 1-6, 7-5, 6-4, 6-7, 12-10.

The world No. 1 was pushed to the limit by Wawrinka in a match that started Sunday evening and ended early Monday local time.

The match, which lasted five hours and one minute, was the best so far of the tournament, the year's first Grand Slam event.

The two players were worn out physically, with Wawrinka being treated by trainers and Djokovic trying to stretch his tight muscles after his biggest test of the tournament.

Djokovic, who beat Spain's Rafael Nadal for the title in a marathon final last year, will now face Czech Tomas Berdych, the No. 5 seed, who defeated South Africa's Kevin Anderson 6-3, 6-2, 7-6 in his Round of 16 match. EFE