MELBOURNE (AFP) - Novak Djokovic says the furnace conditions at the Australian Open were right on the limit, as he won a survival of the fittest battle with Gael Monfils to reach the third round on Thursday (Jan 18).
The six-time champion, now ranked world No. 14, staggered over the finish line to stretch his unbeaten record over Monfils to 15-0, one of the longest at Tour level, after dropping the opening set.
Djokovic, playing in his first tournament for six months after an elbow injury, just did enough at the end to carve out a 4-6, 6-3, 6-1, 6-3 win in 2hr 45min on baking Rod Laver Arena.
The 12-time Grand Slam champion has a day to recover for his third-round encounter with Spanish 21st seed Albert Ramos-Vinolas.
Former US Open champion Juan Martin del Potro, meanwhile, fought off rising Russian Karen Khachanov as he battled through the pain barrier to reach the third round . The Argentine 12th seed needed 3hr 45 min in oppressive court conditions to see off the 47th-ranked youngster 6-4, 7-6 (7-4), 6-7 (0-7), 6-4 on Hisense Arena.
Del Potro, in his first appearance in Melbourne for four years after wrist injuries, will face Czech veteran Tomas Berdych in the third round.
But Belgian seventh seed David Goffin crashed out, losing to Frenchman Julien Benneteau in the second round. He won the opening set but was edged out in a tight tie-breaker for the second set which proved pivotal in the gruelling heat.
Benneteau prevailed 1-6, 7-6 (7-5), 6-1, 7-6 (7-4) in 2hr 54 min to claim his second win over Goffin in three encounters.
The searing heat claimed another big name in 2014 winner Stan Wawrinka - the struggling ninth-seeded Swiss veteran's campaign is over after a convincing 6-2, 6-1, 6-4 defeat by Tennys Sandgren.
The 97th-ranked American will next play Germany's Maximilian Marterer.
It has been tough so far this year for Wawrinka, who was playing in his first tournament since Wimbledon six months ago following left knee surgery.
His compatriot, defending champion Roger Federer, however cooly swept into the third round. The 19-time Grand Slam champion disposed of German Jan-Lennard Struff 6-4, 6-4, 7-6 (7-4), avoiding the worse of the furnace-like conditions in his night match.
"I practise with him so I had the information I needed," he said, adding that the heat does not bother him. "If you want to get to the top, you've got to play in all conditions."
Playing conditions were described as brutal as temperatures hovered around 40 deg C, prompting Djokovic to say a safety limit had been reached for the players.
"People might say at this level you have to be as a professional tennis player fit," he said. "But I think there is a limit, and that is a level of tolerance between being fit and being, I think, in danger in terms of health. It was right at the limit."
"Gael is one of the best athletes in our sport but he was not at his best in the second and third sets. It was about just hanging in there and try to use every opportunity."
Asked about the state of his right elbow, Djokovic added: "It's still not 100 per cent, but it's building. I have a lot of faith and belief in what I am capable of."
The Frenchman, who was often hunched over gasping for air in between points, said it was the hardest match he had played. He added: "I got super dizzy. I think I had a small heatstroke out there.