LONDON: Seven-time champion Roger Federer was stunned by 116th-ranked Sergiy Stakhovsky in the second round of Wimbledon on Wednesday, his earliest loss in a Grand Slam tournament in 10 years. The 27-year-old Ukrainian outplayed Federer on Centre Court, winning 6-7 (5), 7-6 (5), 7-5, 7-6 (5) in one of the biggest upsets in Grand Slam history.

On a chaotic day at Wimbledon when injuries forced seven players to quit, Maria Sharapova managed to play and finish her match.

The end result was the same: Sharapova is out of the tournament. In the second major Wimbledon upset in three days, the third-seeded Sharapova was knocked out of the grass-court Grand Slam by a 131st-ranked qualifier.

The 2004 Wimbledon champion was stunned 6-3, 6-4 by Michelle Larcher de Brito of Portugal in the second round. Sharapova slipped and fell several times on the grass on Court 2 and received medical treatment from the trainer in the second set.

It wasn't serious enough to force Sharapova to quit, as so many others did Wednesday either by walkover or mid-match retirements.

Among the casualties: second-seeded Victoria Azarenka (walkover, right knee), men's No. 6 Jo-Wilfried Tsonga (retirement, left knee), John Isner (retirement, left knee) and Steve Darcis (walkover, right shoulder). Darcis was the man who stunned two-time champion Rafael Nadal in the first round Monday.

Also out: 10th-seeded Marin Cilic (walkover, left knee); 2006 quarterfinalist Radek Stepanek (retirement, left hamstring); and Yaroslava Shvedova (walkover, right arm).

The International Tennis Federation said the seven players forced out is believed to be the most in one day at any Grand Slam event in the 45 years of the Open era.

''I would say (it's a) very black day,'' Cilic said of the spate of injury withdrawals. ''The other days, other weeks, there were no pullouts. Everything just happened today.'' If that wasn't enough, the tournament lost five former No. 1 players Wednesday: Sharapova, Azarenka, Caroline Wozniacki and Ana Ivanovic among the women, and Lleyton Hewitt among the men.

With Azarenka and Sharapova gone, the prospect of Serena Williams lifting the women's trophy for a sixth time look even stronger. Williams, who is riding a 32-match winning streak, had already been considered the overwhelming title favorite.

There were a few moments of normality on this crazy day at the All England Club.

Second-seeded Andy Murray advanced easily to the third round with a 6-3, 6-3, 7-5 victory over Yen-hsun Lu of Taiwan on Court 1. Murray served 11 aces and had 41 winners against only 14 unforced errors for his second consecutive straight-set win. The US Open champion remains on course in his bid to become the first British man to win Wimbledon in 77 years.

The 20-year-old Larcher de Brito played the match of her life against Sharapova on Court 2 to reach the third round of a Grand Slam for only the second time. Larcher de Brito held her nerve in the final 10-minute, 18-point game to serve out the match. She saved two break points and finally converted on her fifth match point when Sharapova hit a forehand into the net.

''I can't believe it,'' Larcher de Brito said. ''I just tried to stay calm. I just played so well. I just hung in there. In the last couple of points or games I just gave it my all and went for it.'' Sharapova tumbled several times on the grass. Trailing 3-2 in the second set, her right leg gave way behind the baseline and she did the splits.

Sharapova took a medical timeout and complained to the umpire about the grass conditions. She said later she believed she strained a hip muscle. ''I don't think I've ever fallen three times in a match before in my career, so that was a little strange,'' Sharapova said. ''But that's certainly not an excuse. ''I think today I've seen a lot of players fall and take a few hits and a few injuries. So I think that's just part of the game, part of what we have to deal with.''

Azarenka, the two-time Australian Open champion, pulled out after hurting her right knee in her opening-round win against Maria Joao Koehler. She withdrew minutes before her second-round match against Flavia Pennetta. Azarenka reached the semifinals at Wimbledon the last two years and had been seeded to face Williams in the final.

It's only the second time in the Open era that a women's player seeded in the top 2 has conceded a match by walkover at any Grand Slam. The last time it happened was in 1974 at the French Open when second-seeded Nancy Richey pulled out before a match. In her match against Koehler, Azarenka did the splits near the baseline, then crumpled to the grass, clutching her right knee and sobbing. She recovered after a medical timeout to win.

Azarenka said on Wednesday that medical tests showed she had a bone bruise rather than a tear but was unable to recover in time. ''We tried to do everything we could, but it was a very significant fall,'' she said. ''To recover in two days after that seemed impossible.''

Murray's victory came not long after his potential quarterfinal opponent, Tsonga, retired with a left knee injury while trailing Ernests Gulbis 3-6, 6-3, 6-3. The Frenchman said he had been experiencing a problem with his knee tendon for a few days and it flared up during the match.