SAN DIEGO, Aug. 3 (UPI) -- Top seed Kim Clijsters and No. 2 Maria Sharapova Thursday advanced to the quarterfinals at the Acura Classic in San Diego.
Clijsters, who was the runner-up at the Acura Classic in 2003, struggled but came back to beat Serb Jelena Jankovic, 6-4, 3-6, 6-3. She will meet eighth-seeded Swiss Martina Hingis in the quarterfinals -- after Hingis beat 12th seed Flavia Pennetta Thursday, 6-2, 3-6, 6-1.
Sharapova easily beat fellow Russian Vera Zvonareva, 6-4, 6-4, to advance to a quarterfinal match against Mary Pierce. The defending champion and sixth seed, Pierce beat Finland's Emma Laine, 6-2, 6-1, Thursday.
In other third-round matches Thursday, fourth-seeded Russian Elena Dementieva beat India's Sania Mirza, 6-2, 3-6, 6-3; fifth seed Patty Schnyder beat Paola Suarez, 6-3, 3-6, 6-1; and No. 7 Nicole Vaidisova beat No. 11 Daniela Hantuchova, 6-4, 6-2. Anna Chakvetadze eliminated 14th seed Ana Ivanovic, 4-6, 6-4, 6-1.
In Friday's matches, Schnyder faces Dementieva, while Vaidisova plays Chakvetadze.
The eventual winner will earn $196,900.