The seventh seed, who reached the final at Wimbledon in July and is the last Russian woman left standing in New York, was too consistent for 31st seed Kanepi and wrapped up victory in one hour, 53 minutes.
Russian Vera Zvonareva reached the semi-finals of the US Open for the first time when she beat Estonia's Kaia Kanepi 6-3 7-5 at a windy Flushing Meadows on Wednesday.
The seventh seed, who reached the final at Wimbledon in July and is the last Russian woman left standing in New York, was too consistent for 31st seed Kanepi and wrapped up victory in one hour, 53 minutes.
Zvonareva, who will play either top seed Caroline Wozniacki of Denmark or unseeded Slovakian Dominika Cibulkova, admitted the swirling winds had played havoc with the match.
"The most important thing was to find the right balance between being patient and being aggressive," said Zvonareva.
"I was trying to make it as difficult as possible for her. With those conditions, unforced errors look like easy shots but with the wind going all different directions and blowing, it's not easy. I think I made the right choices."
Kanepi had beaten fourth seed Jelena Jankovic on her way to the last eight but she looked nervous early on, double-faulting six times and hitting 25 unforced errors in the first set.
When Kanepi did find her range, she had the power to cause Zvonareva problems but the tall Estonian had more trouble than the Russian in coping with the stiff breeze that blew across Arthur Ashe Stadium.
After trading breaks to start the second set, Zvonareva moved ahead 4-2 but Kanepi broke back to level at 4-4.
Kanepi had a chance to break back with the score at 5-5 but Zvonareva held and broke her opponent in the next game to seal her place in the last four.
Kanepi, who made 60 unforced errors in total, admitted she was disappointed but was keen to look at the bigger picture.
"Overall I'm very happy," she said. "I had quite a stable tournament. The matches were not so up and down, so I'm happy about my rhythm."
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