Shaky Djoko reaches quarterfinals

Novak Djokovic’s grip on the Australian Open title looked shaky for a short spell on Sunday but the world number one finally shook off Gilles Simon in a four-and-a-half hour marathon to take his place in the quarterfinals.

Serena Williams, by contrast, booked a rematch of last year’s title decider against Maria Sharapova by sweeping into the quarterfinals without having lost a set, and Roger Federer progressed almost as comfortably to bring the day to a close.

The whiff of an upset hung around Melbourne Park for much of the day – Tomas Berdych, Agnieszka Radwanska and Carla Suarez Navarro all lost opening sets – but it was most potent in Djokovic’s five-setter against Simon.

Djokovic had eased into the fourth round without losing a set as he continued the dominant form that earned him 11 titles, including three of the four grand slams, last year.

Defensive baseliner Simon is a wily campaigner, however, and he elicited 100 unforced errors out of the reigning champion in his 6-3, 6-7(1), 6-4, 4-6, 6-3 defeat.

Hurtling around the arena on legs that have always looked too spindly to take the kind of punishment they regularly endure, the 31-year-old Frenchman absorbed Djokovic’s power and timed his shots to perfection to hurl it back at the Serbian.

Meanwhile, two-time champion Victoria Azarenka reached her fifth Australian Open quarterfinal with a 6-2, 6-4 win over unseeded Czech Barbora Strycova Monday.

The former world number one has been in irresistible form at Melbourne Park, winning her four matches without dropping a set, and had too many weapons for Strycova, who scrapped hard but was edged in the baseline battles.

Azarenka captured the decisive break in the seventh game of the final set and saved two break points at 4-3 before closing out the match in one hour and 26 minutes.

Azarenka’s bid for a third Melbourne Park title continues against German seventh seed Angelique Kerber.

Djokovic has not won five titles at Melbourne Park without being able to negotiate a scrap, however, and despite a string of fluffed drop shots he reasserted his authority in the final set to reach the last eight for a 27th successive grand slam.

“I honestly didn’t expect to make this many unforced errors. In terms of a level that I’ve played, it’s the match to forget for me,” said Djokovic.

“When you’re playing someone like Simon ... you’re trying to cut down on the length of the rallies, go for a winner or go for a dropshot. Sometimes you have a brain freeze, if I can call it that.”

Djokovic’s next opponent, Japan’s Kei Nishikori, must have enjoyed every last minute of the match as he rested up after a straightforward 6-4, 6-2, 6-4 victory over Jo-Wilfried Tsonga.

Nishikori was humiliated 6-1, 6-1 in his last meeting with Djokovic in November and will be hoping to avenge that defeat and revive memories of his stunning upset of the Serbian in the semi-finals of the 2014 US Open.