Caroline Wozniacki reached her first grand slam semi-final since the 2011 US Open with a comprehensive rout of Sara Errani at Flushing Meadows.
No 10 seed Wozniacki, who reached the final in 2009, needed only 65 minutes to beat Errani 6-0 6-1.
Errani, the 13th seed, was unable to hold her serve throughout the match as Wozniacki dominated from the baseline.
Wozniacki will now face Peng Shuai, a player who she has beaten five times in six meetings, for a place in the final.
"It was really tricky conditions with the wind but I tried to stay aggressive," Wozniacki said.
"You always go out there and are a little bit nervous. I served really well after that."
Wozniacki has endured a mixed year in which she has struggled for consistency - however in New York she has shown the sort of form that took her to the top of the world rankings.
"It means so much to me," said Wozniacki.
"It's been a pretty up and down year for me, and to be here in the semi-finals of the US Open again is just incredible."
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