NEW YORK — Grit was not going to be enough to get Maria Sharapova through this one.
Not with nine double faults, including three in a row.
Not with a total of 36 unforced errors.
And certainly not with No. 1-seeded Caroline Wozniacki across the net Monday in the fourth round of the U.S. Open, doing "what she does best," as Sharapova herself put it: getting to nearly every ball and hammering it back, stretching points on and on and on until her opponent misses the mark.
It added up to a 6-3, 6-4 victory for 2009 U.S. Open runnerup Wozniacki over Sharapova, who has failed to make it as far as the quarterfinals at Flushing Meadows since winning the 2006 title.
"I felt like I was playing well out there," Wozniacki said, then made sure everyone understood a key concept by adding, "I made her do those errors."
Indeed, she did. Rare is the opponent who can trade powerful baseline groundstrokes with three-time Grand Slam champion Sharapova and figure out a way to put her on the defensive, but that's exactly what Wozniacki managed to do as early evening shadows crept across the blue court in Arthur Ashe Stadium.
"When she had the opportunity to step in," the 14th-seeded Sharapova said, "she took it and went for her shots."
It's the first victory for Wozniacki in three career meetings against Sharapova, but they hadn't met since 2008. Wozniacki, 20, has an 18-1 record since Wimbledon.
"I've improved a lot, not only physically, but also I believe in myself more. I believe I can do it," said Wozniacki, who is ranked No. 2 but received the top seeding at the U.S. Open because No. 1 Serena Williams withdrew. "Also, I think I can mix up my game a little bit more."
Wozniacki carries a 12-match winning streak into her quarterfinal against Dominika Cibulkova, who eliminated 2004 U.S. Open champion Svetlana Kuznetsova 7-5, 7-6 (7-4).
The other quarterfinal on that side of the draw will be No. 31 Kaia Kanepi against No. 7 Vera Zvonareva, who overwhelmed Andrea Petkovic 6-1, 6-2. Zvonareva, the runnerup at Wimbledon in July, reached the U.S. Open quarterfinals for the first time.
Earlier, Kanepi did the same by coming back to defeat Yanina Wickmayer 0-6, 7-6 (7-2), 6-1.
Third-seeded Novak Djokovic reached the quarterfinals for the fourth consecutive year by outclassing No. 19 Mardy Fish of Tampa 6-3, 6-4, 6-1.
"Sometimes," Fish said, "I sort of get into a rut that it's so much fun for me now, to be able to run down shots and play a little bit of defense, that I do that too much."
Djokovic next faces No. 17 Gael Monfils, a 6-4, 7-5, 7-5 winner over Richard Gasquet.
Five-time champion Roger Federer beat 13th-seeded Jurgen Melzer 6-3, 7-6 (7-4), 6-3. Next up for the second seed is No. 5 Robin Soderling, the player who ended his streak of 23 consecutive Grand Slam semifinals with an upset in this year's French Open quarterfinals. Soderling advanced by eliminating No. 21 Albert Montanes 4-6, 6-3, 6-2, 6-3.