New York:Bothered by swirling gusts and a teen's surprising moxie, Maria Sharapova was completely lost.
Agnieszka Radwanska of Poland pulled off the stunning upset, beating the defending US Open champion 6-4, 1-6, 6-2 in a third-round match that took a startling turn on 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.
No such drama for top-ranked Roger Federer, who proved too much for 6-foot-9 (2.06-meter) American rookie John Isner in a 6-7 (4), 6-2, 6-4, 6-2 victory.
Isner used his booming serve to win the first-set tiebreaker.
"Four months ago, I was unranked," Isner said. "To go from that to beating Roger Federer in a set is pretty cool."
Federer quickly figured Isner out and kept up his bid for a fourth straight Open title.
"I started to pick up on his serve for the second set," Federer said.
Fifth-seeded Andy Roddick breezed, beating 2002 Australia Open champion Thomas Johansson of Sweden 6-3, 6-2, 6-0 to reach the fourth round.
"I've got to try to find myself a hot date later," said Roddick, who's dated actress Mandy Moore and been linked to Sharapova in the past, "so I tried to get off the court a little faster."
In other men's matches, No 4 Nikolay Davydenko of Russia beat No 28 Nicolas Almagro of Spain 7-5, 6-0, 7-5, while No 9 Tomas Berdych of the Czech Republic and No 10 Tommy Haas of Germany advanced.
Donald Young, the 18-year-old American who had never won a Grand Slam match until this tournament, lost to Feliciano Lopez of Spain 3-6, 6-3, 7-6 (5), 7-5.
One minor upset came when No. 19 Andy Murray lost to 43rd-ranked Lee Hyung-taik 6-3, 6-3, 2-6, 7-5. Lee, in the US Open's fourth round for the first time since 2000, will meet No 4 Nikolay Davydenko, who defeated No 28 Nicolas Almagro.
Sharapova wasn't the only Russian to lose to an 18-year-old from Eastern Europe. Slowed by a hip problem, No 7 Nadia Petrova of Russia fell to Agnes Szavay of Hungary 6-4, 6-4.
In other women's matches, sixth-seeded Anna Chakvetadze of Russia beat No 26 Sania Mirza of India, 6-2, 6-3, Victoria Azarenka of Bulgaria beat 1997 champion Martina Hingis 3-6, 6-1, 6-0 and 16-year-old Tamira Paszek of Austria knocked off No 11 Patty Schnyder 4-6, 6-4, 7-6 (1).
"You can see the new generation coming up," Hingis said. "They're very dangerous. I knew it's not going to be easy. My mom texted me. She said, 'Watch out.'"
Sharapova's serve was her undoing, especially after early faults. She won only 23 per cent 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.
Sharapova seemed in charge after she bounced back in the second set and started fast in the next one.
"She destroyed me," Radwanska said.
Sharapova was unhappy she didn't go on with it.
"You'd think I would have the momentum," she said.
It certainly was a different result from their only other meeting - in a May matchup in Istanbul, Sharapova ran away with a 6-love victory in the third set.
Radwanska's lone singles title came in Stockholm this year, and she said her favorite surfaces are grass and clay, rather than the hard courts at Flushing Meadows.
Now into the fourth round at the US Open, she planned to grab her sister - also a tennis pro - and celebrate like a giddy teen. They're going shopping at Louis Vuitton.
Later, she'll think about tennis.
"I'm not favored here," she said. "I have no idea who is next."