Wozniacki books semi-final spot

No.1 seed Caroline Wozniacki overcame a gritty Dominika Cibulkova to book a spot in the semi-finals at the US Open on Wednesday.

Last year's runner-up had cruised through the early rounds at Flushing Meadows this year but had a much tougher time of it against the 45th ranked Slovakian, winning 6-2 7-5 in an hour and 45 minutes.

Wozniacki will now meet Vera Zvonareva in the semi-final after the Russian beat Kaia Kanepi in straight sets earlier on Wednesday.

Errors plagued Cibulkova throughout the match, hitting 43 to just 18 from Wozniacki, although she did hit eight more winners than the world No.2.

After breaking Cibulkova in the opening game, it looked like it was going to be another quick match for Wozniacki, who had lost a total of just 10 games in her previous four matches.

The Slovakian did manage to break back straight away, but the Dane then reeled off the next four games to take a commanding 5-1 lead.

Cibulkova held serve to force 20-year-old Wozniacki to serve for the set, and the No.1 seed had to save two break points before eventually closing it out 6-2.

The second set began as a copy of the first with Wozniacki breaking in the opening game only for Cibulkova to break straight back.

The set stayed on serve as Cibulkova began to cut down on her errors and put pressure on Wozniacki's serve.

She couldn't find a crucial break though, and cracked on her own serve at 5-5 to allow Wozniacki to serve out the match.