NEW YORK — That Maria Sharapova's shaky serving, with a dozen double faults, contributed to her early exit at the U.S. Open came as no surprise.
That her other strokes were problematic Friday could be explained away by the perpetual motion of her third-round opponent, 26th-seeded Flavia Pennetta.
That three-time major champion Sharapova's nerve would fail her in the crucible of a third set? Now that was the real stunner.
Unbeaten this year in 12 previous matches that went the distance, the third-seeded Sharapova dropped the last seven points of a 6-3, 3-6, 6-4 loss to the Italian that took 2½ hours.
"She's a good fighter, you know. You can never give up with her. You have to be focused until the last game; until the last point, actually," Pennetta said. "But I think (at) 5-4, she's starting to feel a little bit of pressure."
After trailing 3-0 and 4-1 in the last set, Sharapova turned things around briefly, getting to 4-all, 15-30 on Pennetta's serve. But the 2006 U.S. Open champion didn't win another point.
"I came back. I had chances. There's no doubt I had chances," Sharapova said. "But I guess (Friday) was the day I didn't take them."
Aside from all of those double faults — including two to begin the final game — Sharapova finished with a total of 60 unforced errors, twice as high as her winner count.
Meanwhile, ninth-seeded Sam Stosur, a Tampa resident, edged No. 24 Nadia Petrova 7-6 (7-5), 6-7 (5-7), 7-5 to reach the fourth round in a match that took 3 hours, 16 minutes — the longest women's match in tournament history (the previous mark: Sybille Bammer defeated Marion Bartoli in 3:05 minutes in 2008).
On the men's side, No. 4 Andy Murray lost the first two sets against 41st-ranked Robin Haase but rallied to win 6-7 (5-7), 2-6, 6-2, 6-0, 6-4.
"At the beginning, I felt sluggish, felt slow," Murray said. "I started forcing myself to get every single ball."
Defending champion Rafael Nadal built a 6-2, 6-2 lead before Nicolas Mahut quit because of an abdominal injury. In an all-American matchup, Andy Roddick reached the third round by beating 18-year-old Jack Sock 6-3, 6-3, 6-4. Other winners included 18th-seeded Juan Martin del Potro and three Americans: Donald Young, who upset No. 14 Stanislas Wawrinka; No. 28 John Isner, a Tampa resident; and Alex Bogomolov Jr.