CARLSBAD, Calif. (AP) -- Top-seeded Vera Zvonareva of Russia beat countrywoman Vera Dushevina 6-3, 6-0 Thursday as the top five seeds advanced at the Mercury Insurance Open.
The third-ranked Zvonareva will face the winner of the night match between No. 12 seed Sabine Lisicki of Germany and American teenager Coco Vandeweghe.
No. 2 seed Andrea Petkovic of Germany and third-seeded Agnieszka Radwanska of Poland also advanced to the quarters with quick victories.
Fifth-seeded Ana Ivanovic advanced to a quarterfinal match against No. 4 seed Peng Shuai of China with a 6-1, 6-2 win against Italy's Alberta Brianti. Peng had to come from a set down and rally from a 1-3 hole in the third set to beat No. 16 seed Sara Errani of Italy 4-6, 6-2, 7-6 (7).
No. 8 Daniela Hantuchova also advanced to the quarters.