Former No. 1 Caroline Wozniacki advanced to the Kremlin Cup semifinals by beating defending champion Dominika Cibulkova 6-2, 6-7 (1), 6-1 on Friday.
Wozniacki won four consecutive games in the first set and later took advantage of an ailing Cibulkova, who was playing with her right hip bandaged and took a medical timeout while trailing 2-1 in the third set.
The third-seeded Wozniacki struggled with her serve in the second set as both players traded breaks four times. The Dane was serving for the match two times later in the set but was broken at love on both occasions. Cibulkova had her left ankle treated.
"It was a very good match today as both of us played very well," Wozniacki said. "The difference at the end was that I just could keep my highest level up to the end and I managed to win most of the important points especially at the beginning of the third set."
The 11th-ranked Wozniacki, who finished the last two seasons at No. 1 on the WTA rankings, still has a chance to overtake Marion Bartoli of France at No. 10 by the end of the season if she wins titles in Moscow and at the season-ending Tournament of Champions, scheduled for Oct. 30 in Sofia, Bulgaria.
In her seventh semifinal this season, Wozniacki will play either Maria Kirilenko of Russia or Sofia Andersson of Sweden.
In the men's tournament, Malek Jaziri became the first Tunisian to reach an ATP semifinals when he beat Lukas Rosol of the Czech Republic 7-6 (5), 6-3.
"I'm really happy," Jaziri said. "I hope I'm lucky enough to make my first ATP final. But anyway, I'm already happy with my performance here."