Former French Open champion Jelena Ostapenko fought back from a set down to reach the second round of the Gippsland Trophy.
The 23-year-old Latvian initially struggled with her serve and posted six double faults in the opening set of her first match since October against experienced Italian Sara Errani.
The 13th seed, who like her opponent has just completed two weeks of quarantine in Melbourne, found her rhythm in the second set and ran out a 4-6 6-3 6-1 winner after just under two hours on 1573 Arena.
'Worst player on the Tour!' - Ostapenko confronts Tomljanovic over fake injury accusation
Estonian Kaia Kanepi had an even bigger scare on Margaret Court Arena against Australian Astra Sharma, who was two points from victory in the second set before slumping to a 1-6 7-5 6-2 defeat.
French 12th seed Caroline Garcia had a more straightforward outing against local Arina Rodionova, winning 6-3 6-4 to set up a second-round meeting with Timea Babos.
Anastasia Potapova thrashed fellow teenager Whitney Osuigwe 6-3 6-0 to set up a date with Simona Halep.
Zheng Saisai, seeded 11th, was making her return to action after 11 months but was knocked out by Romanian Irina-Camelia Begu who came back from a set down to upset the Chinese 3-6 7-5 6-4.
Begu, who is 99 rungs below Zheng in the rankings, converted her third match point after a physical contest that lasted nearly three hours.
- - -
The 2021 Australian Open is live and exclusive on Eurosport. You can watch every moment on eurosport.co.uk and the Eurosport app.
Hsieh happy to avoid a bagel on way to fourth round
'Really scared' - Errani slams umpire after Venus left in agony with knee injury