Six-time champion Novak Djokovic survived a brutal fitness examination to overcome Gael Monfils in intense heat and stagger into the third round at the Australian Open on Thursday.
Djokovic stretched his unbeaten record over Monfils to 15-0, one of the longest at Tour level, after dropping the opening set but just managed to get to the finish line.
He 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.
The extreme elements made it a survival of the fittest with Monfils looking the worse for wear early before Djokovic had enough in the tank to win on his fourth match point in a gruelling eight-minute final game.
"It was brutal conditions and we both suffered, it was a big challenge for both of us, 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 " Djokovic said on-court.
Asked about the state of his right elbow, Djokovic added: "It's still not 100 percent, but it's building. I have a lot of faith and belief in what I am capable of."
It was another step forward for the Serbian former world number one, who had been out of action for six months with elbow trouble.
In contrast, Wimbledon champion Garbine Muguruza refused to blame her heat-blistered feet as she became the biggest casualty of the Australian Open so far on Thursday
The third seed, whose preparation was hampered by a thigh injury, was always trailing against the 88-ranked Hsieh Su-wei from Taiwan before being edged out 7-6 (7/1), 6-4 in one hour and 59 minutes on Rod Laver Arena. "I maybe could have done things better, but at the end, she deserves to win. That's really it," Muguruza told reporters.
Two-time Grand Slam champion Muguruza struggled from the start to keep pace with the tenacious 32-year-old whose last WTA Tour singles title came at Guangzhou back in 2012.
The tall Spaniard had a medical timeout at 2-5 in the first set and after having a blistered foot re-taped looked briefly regalvanized.
Muguruza said her feet were suffering in the heat as temperatures soared above 39. "I think the surface of the court, I don't know how much heat, it's terrible, very, very hot, and it's easy to get blisters and red," i don't think that was the reason why today it didn't go my way. It was already wrapped (foot), but very quickly I started to feel a blister was coming, and I'd rather prevent it than having the problem after." she said.
Muguruza then broke back twice but Hsieh, who works closely with former Australian Open tournament director Paul McNamee, ran away with the tiebreak 7-1.
Muguruza saved a first match point in the second set to get back to 5-4 but Hsieh made no mistake in the next game. "I knew she was going to give me a lot of pressure, at 5-4 I thought I'd keep hanging there and try and take my spot," said Hsieh, who was ranked number one in doubles for five weeks in 2014.
"It's never easy to play against top 20 girls. I think mentally for sure they are much better, so when we go on the court we have to forget who we are playing and focus on our game."