Leading seeds Lindsay Davenport, Serena Williams and Anastasia Myskina won second-round matches on Wednesday and reached the Dubai Women's Open quarterfinals.
World No. 1 Davenport defeated China's Jie Zheng 6-2, 7-5, while Australian Open champion Williams survived an early scare to beat Russia's Elena Bovina 1-6, 6-1, 6-4.
French Open champion and No. 3-seeded Myskina advance when Marion Bartoli of France retired with left knee tendinitis while trailing 4-2.
Davenport's quarterfinal opponent on Thursday will be another former Wimbledon champion, Conchita Martinez, who ousted seventh-seeded Nathalie Dechy of France 6-1, 6-2.
Williams will meet Daniela Hantuchova of Slovakia, who beat Elena Likhovtseva of Russia 7-5, 6-4, and Myskina faces eighth-seeded Patty Schnyder of Switzerland, who downed Li Na of China 6-3, 7-6 (8).
The other quarterfinal pits wild card Sania Mirza of India against Jelena Jankovic of Serbia and Montenegro, who both won on Tuesday.
Davenport won the last four games to vanquish Jie, a qualifier.
"I started well and finished well, but played some so-so games in the middle," said Davenport, who had a first-round bye.
She has reached the final of her last two events, the Tokyo Indoors last month, and the Australian Open in January, when she crushed Martinez in the first round to level their head-to-head record at 8.
Williams, making her first tour appearance since a stomach illness forced her to withdrew before the Paris Indoor quarterfinals last month, lost the opening five games to Bovina and the first set 6-1, raising fears she would follow sister Venus out of the tournament.