Highlights: Australian Open day seven

MELBOURNE (Reuters) - Defending Australian Open champion Novak Djokovic battled through discomfort from a side injury to win his 300th Grand Slam match in a 7-6(4) 4-6 6-1 6-4 victory over Canada's Milos Raonic on Sunday.

Djokovic had not hit a tennis ball since his five-set epic against Taylor Fritz two days ago, skipping practice to recover to play Raonic and the Serb kept his bid for a record-extending ninth title in Melbourne alive.

"If it's any other tournament than a Grand Slam, I would withdraw from the event, for sure," Djokovic said. "I didn't know before I finished my warm-up whether I'm going to play or not."

Djokovic faces Alexander Zverev in the quarter-finals after the German advanced with a clinical 6-4 7-6(5) 6-3 victory over Dusan Lajovic.

The last eight proved a step too far for Dominic Thiem, however, after the third seed was dumped in straight sets by Bulgarian Grigor Dimitrov.

"I'm not a machine," said the Austrian who struggled to find the intensity with which he had mounted a comeback to beat Nick Kyrgios in five sets in the previous round.

Canadian 20th seed Felix Auger Aliassime seemed to be cruising as well after taking a two-set lead but was upset by Russian Grand Slam debutant Aslan Karatsev 3-6 1-6 6-3 6-3 6-4.

Simona Halep took revenge for her French Open loss to Iga Swiatek last year by beating the Polish teenager 3-6 6-1 6-4 to set up a clash with Serena Williams who ousted seventh seed Aryna Sabalenka 6-4 2-6 6-4.

U.S. Open champion Naomi Osaka teetered on the brink of elimination but the third seed saved two match points to see off Garbine Muguruza 4-6 6-4 7-5.

Highlights of day seven of the Australian Open tennis championships at Melbourne Park on Sunday. Times local (GMT +11):

MONDAY, 0025 BATTLE-SCARRED DJOKOVIC ADVANCES

Defending champion Novak Djokovic allayed muscle injury fears to overcome Milos Raonic 7-6(4) 4-6 6-1 6-4 for his 300th Grand Slam match win to set up a quarter-final clash with Alexander Zverev.

2110 ZVEREV MARCHES INTO QUARTERS

Sixth seed Alexander Zverev booked his quarter-final spot with a 6-4 7-6(5) 6-3 victory over Serbia's Dusan Lajovic.

2105 HALEP GETS REVENGE ON SWIATEK

Romanian second seed Simona Halep came from behind to beat Iga Swiatek 3-6 6-1 6-4 and avenge her defeat by the Polish teenager at last year's French Open.

Halep will face Serena Williams in the quarter-finals as the pair meet for the first time since the Romanian triumphed 6-2 6-2 in the 2019 Wimbledon final.

1830 THIEM KNOCKED OUT

U.S. Open champion Dominic Thiem's Melbourne Park campaign ended in the fourth round after he was beaten 6-4 6-4 6-0 by Bulgarian Grigor Dimitrov in just over two hours.

1615 KARATSEV STUNS AUGER-ALIASSIME IN FIVE-SET EPIC

Russian qualifier Aslan Karatsev erased a two-set deficit to beat Canada's 20th seed Felix Auger-Aliassime 3-6 1-6 6-3 6-3 6-4.

1545 SERENA PASSES SABALENKA TEST

American Serena Williams, chasing a record-equalling 24th Grand Slam title, held off a spirited challenge from seventh seed Aryna Sabalenka 6-4 2-6 6-4 to reach the quarter-finals.

1255 OSAKA BATTLES PAST MUGURUZA

Third seed Naomi Osaka saved two match points as she rallied from a set down to beat last year's finalist Garbine Muguruza 4-6 6-4 7-5.

1219 HSIEH REACHES FIRST GRAND SLAM QUARTER-FINAL

Taiwan's Hsieh Su-wei reached the first Grand Slam quarter-final of her lengthy career when she shocked Czech 19th seed Marketa Vondrousova 6-4 6-2 on Margaret Court Arena.

At 35, Hsieh will be the oldest player to make a Grand Slam quarter-final debut in the open era when she plays Naomi Osaka later this week.

11.10 PLAY UNDERWAY ON DAY SEVEN

Play got underway as scheduled on the second day of Victoria's snap five-day coronavirus lockdown, which has resulted in fans being shut out of Melbourne Park.

Two new locally acquired cases of COVID-19 were reported in the state in the 24 hours to Sunday morning.

The temperature was a cool 18 degrees Celsius (64 degrees Fahrenheit) with some sunshine forecast for the afternoon.

(Reporting by Nick Mulvenney, Hardik Vyas and Rohith Nair; Editing by Peter Rutherford and Ed Osmond)