Serena survives Sabalenka scare to enter last 8
MELBOURNE: Australian Open champion Novak Djokovic came through a tough examination of his fitness as the top seed beat Canadian powerhouse Milos Raonic 7-6 (4), 4-6, 6-1, 6-4 on Sunday to reach the quarter-finals.
Djokovic, who injured a side muscle during a five-set win over Taylor Fritz on Friday and suggested he might not be able to continue, showed hints of discomfort on the way to becoming only the second player to reach 300 Grand Slam match wins.
Fourteenth seed Raonic had never previously taken a set off Djokovic in three previous Grand Slam meetings so when he snatched the second set a surprise looked possible.
But Djokovic, bidding for a record-extending ninth title in Melbourne, responded by raising his level and improving his record over Raonic to 12-0.
The Serb will face Germany's Alexander Zverev for a place in the semi-finals.
Third seed Dominic Thiem slumped out of the Australian Open in the fourth round , comprehensively beaten 6-4, 6-4, 6-0 by Bulgarian Grigor Dimitrov on Rod Laver Arena.
The US Open champion, who came back from two sets down to beat Nick Kyrgios in the third round on Friday, looked out of sorts from the beginning of the contest.
The first two sets followed the same pattern with Thiem taking an early 3-1 lead only for 18th seed Dimitrov to charge back at him and clinch the set.
The Austrian, losing finalist here last year, was unable to rouse himself in the third set and Dimitrov sealed a last-eight meeting with Russian qualifier Aslan Karatsev after little more than two hours on court.
Second seed Simona Halep survived a first-set wobble to beat Iga Swiatek 3-6, 6-1, 6-4 as the Romanian avenged her shock defeat by the Polish teenager at the same stage of last year's French Open.
Swiatek, who knocked out Halep en route to her maiden Grand Slam title in Paris, used her booming groundstrokes to save two break points in the seventh game before immediately breaking the Romanian to love on her way to claiming the opening set.
Halep roared back with an early break in the second set as her crafty baseline play frustrated her teenage opponent, who made a string of errors.
The Romanian reeled off five consecutive games across the second and third sets before sealing victory in just under two hours at Rod Laver Arena.
Serena Williams stormed into the quarter-finals with a gritty 6-4, 2-6, 6-4 victory over Belarusian Aryna Sabalenka.
The match was a big test for Williams, who was up against one of the few players on the women's tour capable of matching her power from behind the baseline.
"I'm happy to get through that one," Williams said in an on-court interview. "It wasn't easy and I knew it wasn't going to be easy. She was teeing off on every shot.
"Even the games that I lost were super close, one shot here and one shot there, and I just felt like, 'Serena you've got this, you've just got to keep going.'"
German sixth seed Alexander Zverev used his powerful serve to good effect to overcome 23rd seed Dusan Lajovic of Serbia 6-4, 7-6 (5), 6-3 and reach quarter-finals.
Zverev needed five sets to beat Lajovic in each of their two previous meetings at the French Open, but the 23-year-old was in a more ruthless mood on Margaret Court Arena and sealed victory with his 15th ace.
The German got 72% of his first serves in and racked up 44 winners to dominate the 30-year-old Lajovic throughout the match.
Russian qualifier Aslan Karatsev continued his fairytale run at the Australian Open, reaching the quarter-finals on his Grand Slam debut with a 3-6, 1-6, 6-3, 6-3, 6-4 win over 20th seed Felix Auger-Aliassime.
Naomi Osaka saved two match-points as she battled back from the brink to reach the quarter-finals with a 4-6, 6-4, 7-5 victory over in-form Garbine Muguruza. Agencies