The defending champion had been taken the distance in her opening two matches in Melbourne but was able to wrap up her third round match 6-0 6-4 in an assured display.

Eighth seed Svetlana Kuznetsova had another mammoth battle at the first major of the year as she squeezed past former semi-finalist Jelena Jankovic 6-4 5-7 9-7, the pair spending nearly four hours on court.

Anastasia Pavlyuchenkova, Coco Vandeweghe and Mona Barthel also needed three sets to seal their progression, while Sorana Cirstea beat Alison Riske 6-2 7-6 (7-2).

Seven-time grand slam winner Venus Williams was ruthless in her destruction of Duan Ying-Ying, the 2003 runner-up needing less than an hour to complete a comprehensive 6-1 6-0 triumph.

There were no problems for seventh seed Garbine Muguruza either, as she breezed past Anastasija Sevastova 6-4 6-2.