Defending champion Daniela Hantuchova ousted Vania King of the United States 7-6 (7), 6-4 Friday to reach the semifinals at the Pattaya Open.
The Slovak remained unbeaten against King with a 7-0 record.
Hantuchova will face Taiwanese qualifier Hsieh Su-wei, who beat Sania Mirza of India 7-5, 6-3.
Sorana Cirstea of Romania reached semifinal when top-seeded Vera Zvonareva of Russia retired with a left hip injury. The match was tied 2-6, 6-4, 2-2 when Zvonareva pulled out.
"I rushed too much in the first set. Then I tried to be more patient and made her play more while my serves and returns were better in the second set," Cirstea said. "However, I didn't notice that she was injured and was surprised she retired. I hope she will recover soon."
Fourth-seeded Maria Kirilenko of Russia ended the local hopes for Tamarine Tanasugarn, 7-6 (2), 6-1, and will face Cirstea.