TOKYO -- Eugenie Bouchard of Canada outlasted ninth-seeded Sloane Stephens of the United States, 5-7, 7-6 (7), 6-3 on Tuesday to reach the third round of the Pan Pacific Open.
Bouchard now advances to play sixth-seeded Jelena Jankovic in the the third round.
In other second-round matches, Svetlana Kuznetsova of Russia upset third-seeded Sara Errani of Italy 6-4, 6-4.
Kuznetsova, a two-time major winner, hit seven aces in the match and will next face 15th-seeded Sorana Cirstea of Romania. Cirstea beat Japanese wildcard Misaki Doi 6-1, 6-2.
No. 11-seeded Ana Ivanovic of Serbia beat Elina Svitolina of Ukraine, 6-3, 6-0, and 16th-seeded Dominika Cibulkova of Slovakia defeated Casey Dellacqua of Australia 7-5, 6-3.
Venus Williams faces top-seeded Victoria Azarenka later Tuesday.
Serena Williams pulled out of the $2.3 million tournament to recover from a busy summer schedule.