China's Li Na defeated Anastasia Pavlyuchenkova of Russia 7-5, 4-6, 6-2 on Tuesday to advance to the third round of the Pan Pacific Open.
The seventh-seeded Li sealed the win when she broke Pavlyuchenkova in the final game and will next face the winner of Tuesday's late second-round match between 10th-seeded Caroline Wozniacki and Daniela Hantuchova.
In other matches, Croatia's Petra Martic upset fourth-seeded Petra Kvitova 6-4, 6-4 while fifth-seeded Angelique Kerber of Germany downed Japan's Ayumi Morita 6-3, 6-4.
No. 9-seeded Marion Bartoli of France beat Germany's Julia Goerges 6-2, 7-5.
Top-ranked Victoria Azarenka faces Austria's Tamira Paszek later Tuesday.