Fifth-seeded Angelique Kerber of Germany beat Dominika Cibulkova of Slovakia 7-6 (5), 7-5 on Monday to move into the second round of the Sydney International, one of the last warm-up tournaments for the Australian Open starting next week.
Kerber will next play Estonia's Kaia Kanepi, who beat American qualifier Victoria Duval 6-1, 6-3.
In other first-round matches, Lucie Safarova beat 2010 French Open champion Francesca Schiavone 6-4, 6-4 and American Bethanie Mattek-Sands had a 6-4, 6-3 win over Canada's Eugenie Bouchard.
Two other U.S. players advanced, with Lauren Davis beating Australia's Jarmila Gajdosova 6-4, 7-6 (8) and Varvara Lepchenko scoring a 6-3, 3-6, 7-5 win over two-time major winner Svetlana Kuznetsova of Russia. Tsvetana Pironkova of Bulgaria beat Sorana Cirstea of Romania 6-4, 6-1.