Sara Errani of Italy beat France's Marion Bartoli 3-6, 6-2, 6-2 on Wednesday to advance to the quarterfinals of the Pan Pacific Open.
After struggling in the first set, the sixth-seeded Errani broke No. 9 Bartoli in the second game of the second set and never looked back.
"It was a tough match on this fast court," Errani said. "I didn't start off well but neither did she. She got a little tired in the second set and that's when I started to play better."
Errani, who has won three WTA titles this year, will face the winner of Wednesday's third-round match between Nadia Petrova and Petra Martic in the quarterfinals.
In other matches, eighth-seeded Samantha Stosur of Australia beat Dominika Cibulkova of Slovakia 6-4, 7-5 while No. 17 Nadia Petrova of Russia beat Croatia's Petra Martic 7-6 (2), 6-7 (1), 6-4.
Top-ranked Victoria Azarenka of Belarus faces 14th-seeded Roberta Vinci of Italy later Wednesday while two-time champion Maria Sharapova of Russia, seeded second, takes on Lucie Safarova of the Czech Republic.