The weakest part of Sharapova's game was undoubtedly her serve, as she gave Wozniacki the only break of the opening set when, from leading 40-30 in the fourth game, she produced three consecutive double-faults.

Sharapova's serve failed her again in the second set when she double-faulted in the seventh game to provide Wozniacki with the only break.

In all, Sharapova double-faulted nine-times.

Sharapova was 2-0 lifetime against the 20-year-old Dane, with both matches coming in 2008.

"I felt like I played a couple of good points and then make an easy error, hit a return long or miss a first serve, give her many looks at second-serve returns," said Sharapova.

"I think it just needs to be more stable and not so up and down, especially against an opponent like her.

"I need to string a few more things together than I did. It's all really capitalizing on what you have. You work hard for something, and then you let it slip away. I think I've just got to capitalize on that."

Wozniacki has won 12 straight and 18 of her last 19 matches, including titles in her last two events, in Montreal and New Haven.

 Svetlana Kuznetsova of Russia hits a return to Dominika Cibulkova of Slovakia during the U.S. Open tennis tournament in New York, September 6, 2010.

Cibulkova dismissed Kuznetsova in two hours, six minutes, as the erratic Russian piled up 10 double faults and had her serve broken on four occasions.

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