(Updates with Federer upset)

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Roger Federer suffered a shocking upset at Wimbledon on Wednesday, falling in the second round to unheralded Ukrainian Sergiy Stakhovsky 6-7 (5-7), 7-6 (7-5), 7-5, 7-6 (7-5).

Two days after arch-rival Rafael Nadal was bounced from the tournament in straight sets by 135th-ranked Belgian Steve Darcis, Federer, a seven-time champion at the All England Club, lost a nip-and-tuck battle against the world's 116th-ranked player.

Federer struggled all match to break through against Stakhovsky's serve, converting just one of his eight break points throughout the three-hour contest.

The Swiss No. 3 seed got off to a sluggish start and was unable to put any separation between himself and the Ukrainian in the first set, although he used his experience to pull out the tiebreaker.

Stakhovsky kept the pressure on, winning the second set in a tiebreaker and then recording the first break of serve of the match in the third set when Federer misplayed a backhand in the 11th game. The 27-year-old underdog then proceeded to hold serve to take a two-set-to-one lead.

Worry was written on Federer's face when he went down an early break in the fourth set, although he still could hope Stakhovsky might freeze up when trying to close the match out.

That nearly happened when the Ukrainian blew the service-break lead, but Stakhovsky's nerves held up in the tiebreaker and he clinched victory when Federer missed a backhand wide.

The loss broke a string of 36 consecutive quarterfinal berths at Grand Slam events for the 31-year-old Swiss, who had not lost before the third round of a major since the 2003 French Open.

This year's Wimbledon also marked the first Grand Slam event in which both Federer and Nadal were in the draw yet neither reached the second week of the tournament.

Those two players had been expected to meet in the quarterfinals of this year's event.

Federer, winner of a record 17 Grand Slam men's singles titles, was not the only highly seeded player to exit Wimbledon on Wednesday.

Earlier in the day, the No. 2 seed in the women's draw, Victoria Azarenka, pulled out of her scheduled second-round match against Italy's Flavia Pennetta with a knee injury.

Third-seeded Maria Sharapova was then stunned by 131st-ranked Michelle Larcher De Brito of Portugal 6-3, 6-4, also in second-round action.

In another significant development on the men's side, French No. 6 seed Jo-Wilfried Tsonga, a semifinalist at Wimbledon the past two years, was forced to retire from his match against dangerous Latvian Ernests Gulbis while trailing two sets to one.

Tsonga and Azarenka, who had twisted her knee in a hard fall in a first-round victory, were two of seven singles players to either withdraw or retire from their matches on Wednesday.

Several other players slipped and fell on Wednesday and complained about the slick court conditions. EFE