Japan’s Kei Nishikori will be Murray’s surprise opponent in the quarters after his stunning five-set victory over former finalist Jo-Wilfried Tsonga —Reuters Photo

MELBOURNE: Defending champion Novak Djokovic repulsed a tenacious fightback from Lleyton Hewitt to join last year’s finalist Andy Murray in the quarter-finals of the Australian Open on Monday.

The Serb world number one was tested for the first time and dropped his only set of the tournament so far before extinguishing Hewitt’s challenge, 6-1, 6-3, 4-6, 6-3 in almost three hours.

Djokovic will now face Spanish fifth seed David Ferrer in Wednesday’s quarter-finals after Ferrer’s straight-sets win over Frenchman Richard Gasquet.

The Serbian world number one was in command for the opening two sets before the fiercely competitive Australian veteran hit back, taking the match into a fourth set.

“It was a really big challenge for me tonight to see where I stand,” Djokovic said.

“I think I’ve been handling it really well because I could easily get my emotions out as I usually did.” Murray, the British fourth seed, was on court for only 49 minutes before his Kazakh opponent Mikhail Kukushkin retired early in the third set with a hip flexor injury.

Murray said he was looking to hit the practice courts to retain his sharpness ahead of Wednesday’s quarter-final after Kukushkin pulled out while trailing 6-1, 6-1, 1-0.

The Scot admitted he was bored by his one-sided match with struggling Kukushkin.

“Yeah, it’s just boring. There was nothing happening on the court,” Murray said of the match against his 92nd-ranked opponent.

“I didn’t have to do anything. Just hitting the ball in the court and he wasn’t running. He was making mistakes the first or second ball of the rally,” said Murray.

Murray, a beaten finalist in the past two Australian Opens, said while he was happy to conserve energy in the sapping heat, he needed to put in some work to prepare for tougher matches ahead.

“It’s perfect because you conserve energy. You just need to make sure, you know, today and tomorrow you hit enough balls to make sure you don’t lose any rhythm.

“But you can’t look at it as a negative. At this stage of the tournament to be off the court in 45 minutes or so isn’t bad.”

Japan’s Kei Nishikori will be Murray’s surprise opponent in the quarters after his stunning five-set victory over former finalist Jo-Wilfried Tsonga on Monday.

Nishikori became the first Japanese man into the Australian quarter-finals in 80 years when he upset the French sixth seed, 2-6, 6-2, 6-1, 3-6, 6-3 in scorching conditions to earn a place in the last eight.

It is the best result at a grand slam for Nishikori, who also became only the second Japanese man to reach a major quarter-final in the open era since Shuzo Matsuoka at Wimbledon in 1995.

“I was just playing one point at a time and it was not easy conditions today, Jo-Wilfried was playing well and I was just trying my best,” Nishikori said.

“Hopefully it’s big news in Japan. A lot of people have messaged me since my last win, so now it’s a quarter-final and I’m really excited.”Tsonga said Nishikori proved a difficult opponent in the heat.

“When you have a guy in front of you who returns everything, even when you serve at 215 (kilometres per hour, 134 miles an hour), it puts lot of pressure on you,” he said.

“It’s tough to play against him because he runs a lot and everything’s coming back.”