Amanmuradova, playing in her hometown, edged Jill Craybas 7-5, 6-7 (6-8) 6-2 in a match that took nearly 2 1/2 hours. She seemed to wear Craybas down, breaking open the tight match in the third set when she didn't face a break point and finished off both break chances she created.
No. 1-seeded Alexandra Dulgheru also needed three sets before reaching the quarterfinals with a 4-6, 6-1, 7-5 win over Ekaterina Bychkova.
The tournament lost three seeded players Wednesday, including No. 3 Anna Chakvetadze, who retired because of illness. She was trailing Evgeniya Rodina 7-6 (7-4), 3-2 when the match ended.
Darya Kustova ousted sixth-seeded Magdalena Rybarikova 6-2, 4-6, 6-3 and Stefanie Voegele was a 6-4, 6-1 winner over No. 8-seeded Maria Elena Camerin in the day's upsets.
Fourth-seeded Elena Vesnina breezed by Olga Savchuk 6-2, 6-2 and No. 7-seeded Alla Kudryavtseva topped Alexandra Panova 6-4, 6-4 but fifth-seeded Monica Niculescu escaped Ekaterina Ivanova 0-6, 6-0, 6-1. Niculescu lost only a total of 20 points in the second and third sets after the shaky start.