Top-seeded Alexandra Dulgheru of Romania rallied to beat Ekaterina Bychkova of Russia 4-6, 6-1, 7-5 Wednesday and advance to the quarterfinals of the Tashkent Open.
Second-seeded Akgul Amanmuradova of Uzbekistan also advanced, beating American veteran Jill Craybas 7-5, 6-7 (6), 6-2.
Stefanie Voegele of Switzerland advanced to her second quarterfinal this season, beating eighth-seeded Maria Elena Camerin of Italy 6-4, 6-1 in the first upset of the tournament.
''I've played her twice and lost,'' Voegele said. ''Today, I tried to play every point against her. It was tough to work for every point.''
Also Wednesday, third-seeded Anna Chakvetadze of Russia had to retire with flu when trailing 7-6 (4), 3-2 against compatriot Evgeniya Rodina. The illness will force Chakvetadze to miss next week's China Open in Beijing.
In another upset, Darya Kustova of Belarus ousted sixth-seeded Magdalena Rybarikova of Slovakia, 6-2, 4-6, 6-3.
The 27th-ranked Dulgheru, who won her second career title in May in Warsaw, Poland, won four consecutive games in the second set to stay in the match. She broke decisively in the 11th game of the third and then served out the match.
''I am happy to survive. It was a close match,'' Dulgheru said. ''I made some crucial mistakes, which took the match into a close finish. Bychkova played well and I am happy to close and finish the match.''
In Thursday's quarterfinals, Dulgheru will play compatriot Monica Niculescu, seeded fifth, who rallied to beat Russia's Ekaterina Ivanova 0-6, 6-0, 6-1.
Fourth-seeded Elena Vesnina and her fellow Russian Alla Kudryavtseva, seed No. 7, also advanced.
