Former World No. 1 Amelie Mauresmo of France and fourth-seeded Russian Elena Dementieva each posted quarterfinal wins Friday at the $585,000 Advanta Championships. The third-seeded Mauresmo downed American Mashona Washington 6-3, 6-4, while Dementieva rallied to beat Czech Kveta Peschke 4-6, 6-0, 6-3. Mauresmo, the two-time defending champion, will next take on red-hot Czech Nicole Vaidisova in the semis. The seventh-seeded Vaidisova, who has won 18 straight matches, which includes three consecutive titles, advanced to the round of four with a victory over crowd favorite Lisa Raymond 6-4, 6-1. Raymond is from nearby Wayne, PA. Up next for Dementieva will be a meeting with countrywoman Nadia Petrova. The sixth-seeded Petrova, who titled last week in Linz, moved into the semifinals with a 7-5, 7-6 (7-5) win over Martina Sucha of the Czech Republic. Dementieva's win clinched her spot in next week's WTA Tour Championships. Mauresmo is the highest seed playing this week after American Lindsay Davenport and Russian Maria Sharapova withdrew earlier in the week. Davenport, the top seed, is ailing from the flu and Sharapova, the two seed, suffered a right thumb sprain during off-court training. This week's winner will pocket $93,000.