Wozniacki defeated Sofia Arvidsson, 7-6, 6-2, and will face sixth-seeded Dominika Cibulkova in Thursday's Quarterfinals. Kvitova made quick work of American Nicole Gibbs and won, 6-2, 6-4 in straight sets and will face Lucie Safarova.
Up-and-comer, 25-year-old Russian Maria Kirilenko advanced on a walkout against Germany's Mona Barthel and will face Olga Govortsova of Belarus, who on Tuesday upset No. 1 seed Agnieszka Radwanska after Radwanska withdrew with a shoulder injury.
Govortsova, who had to qualify to gain entry into the tournament, is the only unseeded player left in the event.
Matches for the event will take place through Saturday, August 25, when the Finals will be held at 12:30 p.m.
Thursday's matches will begin at 1:00 p.m. ET and will be broadcast on ESPN 2 from 1:00 p.m. to 3:00 p.m.
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