Agnieszka Radwanska of Poland pulled off the stunning upset, beating the defending U.S. Open champion 6-4, 1-6, 6-2 in a third-round match that took a startling turn Saturday.

Sharapova seemed to take control by winning eight games in a row, giving her a 2-0 lead in the final set. Then, she fell apart and dropped the last six games.

"I could sit here and blame the wind and blame my opponent. But there are no excuses," Sharapova said. "I'm not going to throw myself a pity party here."

Sharapova became the first No. 2-seeded woman to lose before the round of 16 at the Open since Andrea Jaeger in 1981. Her father could barely stand to watch, moving from his front-row perch to a seat farther back during the final points.

The 30th-ranked Radwanska had a lot to do with Sharapova's undoing. At 18, the former junior champ at Wimbledon and the French Open played with poise and smarts, creeping closer and closer to the service box on second serves, hoping to unnerve the two-time Grand Slam winner.

At times, Radwanska walked nearly halfway from the baseline to the net as Sharapova got ready, then backed off at the last second.

"I knew that she hates it if somebody is moving on the serve," Radwanska said, her braces gleaming in the sunlight. "She made many mistakes."

A shrewd move by Radwanska. Maybe make that a shrew move - away from the court, she likes to play with her pet rats.

"I don't worry about what my opponent is doing," Sharapova said.

Sharapova's serve was her undoing, especially after early faults. She won only 23 percent of her second-serve points and wrecked herself with 12 double-faults.

The 6-foot-2 (1.88-meter) Sharapova's high toss is particularly susceptible to gusts, the same way popups often blow crazily across the street at Shea Stadium. She frequently stood still, waiting for the wind to subside.

Playing in the glare of a morning match, Sharapova put on a sun visor early. Dressed in white instead of her power-red night outfit, Sharapova finished with 49 unforced errors - she had only 25 in losing a total of two games in her first two matches.