New York :Top seed Caroline Wozniacki will play Vera Zvonareva of Russia in Friday's semi-finals at the US Open after both battled their way through wind-swept last eight games on Wednesday.
Wozniacki, a 20-year-old Dane who was runner-up here last year and who has cemented her position as a top player this year, defeated Dominika Cibulkova of Slovakia 6-2, 7-5.
Zvonareva, a temperamental 26-year-old Russian who mastered her emotions this year to reach the Wimbledon final in July, defeated Kaia Kanepi of Estonia 6-3, 7-5.
The other semi-final, which was decided on Tuesday, will send defending champion and second seed Kim Clijsters of Belgium against third seed Venus Williams of the United States.
The blustery conditions, which have buffeted the Flushing Meadows complex since Hurricane Earl swept past off Long Island at the weekend, seemed to worsen on the Arthur Ashe Stadium court, the biggest purpose-built tennis arena in the world.
Wozniacki, who had lost just 10 games through four rounds, including a big win over former champion Maria Sharapova to reach the last eight, looked flustered at times as her normally impeccable timing was skewed by the wind.
She won the first set easily enough, but the small-in-stature Cibulkova started to put more pressure on her in the second set after annulling a service break in the first game.
Wozniacki held firm against an increasingly aggressive Cibulkova and grabbed the break of serve she needed in the 11th game to go 6-5 up.
Cibulkova had a point to break back, but she netted a forehand after one of the longest rallies in the match and Wozniacki promptly finished her off.
"It was really difficult to play today," the Dane said.
"It was very windy, and from one side you barely hit it and the ball was flying, and from the other side you had to really hit through because the ball didn't go anywhere."
Zvonareva, who had a spectacular emotional meltdown here last year when she squandered six match points in a fourth round tie against Italy's Flavia Penetta, was made to work hard for her win against Kanepi, one of the most improved players on the circuit in the last few months.
The Russian comfortably pocketed the first set, but the second set opened with four straight breaks of serve as both players continued to struggle with the blustery conditions.
Zvonareva finally held serve to take a 3-2 lead and then broke again in the following game.
Kanepi hit back once again to level at 4-4, but after failing to convert two break points against Zvonareva in the 11th game, she lost her serve for a final time as Zvonareva swept into her second straight Grand Slam semi-final.
"It was very tough today for both of us," said Zvonareva.
"We tried to show our best, but at times we had some ridiculous rallies.
"In these conditions you had to find the right balance between being aggressive and being patient and I was able to find that balance."
Wozniacki and Zvonareva have played each other four times with each winning two games.