Top-seeded Russians Nikolay Davydenko and Svetlana Kuznetsova booked their quarter-final berths on Wednesday at the Pilot Pen hardcourt tournament. Meanwwhile, second-seeded Verdasco overcame Italy's Andreas Seppi 7-6 (3) 6-2 to enter quarters.
Davydenko defeated France’s Fabrice Santoro 7-5, 6-3 and will now face sixth-seeded American Sam Querrey in the quarters. Querrey downed Germany's Bjorn Phau 7-5, 6-3. French Open champion Kuznetsova clawed her way past Belgian teenager Yanina Wickmayer 6-4, 5-7, 7-6 (7/2).
Defending women's champion and second seed Caroline Wozniacki also advanced to the quarter-finals, defeating rising Russian Anastasia Pavlyuchenkova 6-1, 6-4.
Kuznetsova will play eighth-seeded Amelie Mauresmo in the quarter-finals on Thursday.