Azarenka, Steve Darcis and John Isner all pull out with injuries at Wimbledon

LONDON — Injuries knocked three key players out of Wimbledon on Wednesday — second-seeded Victoria Azarenka, the man who stunned Rafael Nadal in the first round and the American man who won the longest match in tennis history.

The start of Day 3 of the grass-court Grand Slam was less about the tennis results and more about a casualty list that included Azarenka, Steve Darcis and John Isner.

Also withdrawing with injuries were 10th-seeded Marin Cilic (left knee) and 2006 quarterfinalist Radek Stepanek (left hamstring).

The tournament also lost a former champion, 2002 winner Lleyton Hewitt, but he managed to play a match. The Australian was ousted by 189th-ranked German qualifier Dustin Brown, 6-4, 6-4, 6-7 (3), 6-2.

The dreadlocked Brown, who switched nationality from Jamaican to German in 2010, was in tears after beating the former No. 1-ranked player. Brown has played mainly on the lower-tier challenger circuit in 2013 and had never won a match at Wimbledon until this year.

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 was to begin.

Azarenka reached the semifinals at Wimbledon the last two years and had been seeded to face five-time champion Serena Williams in the final.

Azarenka recovered after a medical timeout to finish out the 6-1, 6-2 victory on Monday but she moved gingerly after falling and said she wasn't sure about the extent of the injury.

Azarenka said 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 as possible, but it was just very significant fall," she said. "To recover in two days after that seems impossible with the compensation on the entire body by finishing that match."

Steve Darcis, the 135th-ranked Belgian who beat two-time champion Nadal in straight sets on Monday in one of Wimbledon's greatest upsets, pulled out because of a right shoulder injury.

Darcis, who had been scheduled to play Lukasz Kubot of Poland, said he hurt his shoulder while diving for a shot in the first set against Nadal.

Darcis had become an overnight sensation after beating the eight-time French Open champion and holder of 12 Grand Slam titles.

"When you beat a guy like Rafa first round, you want to show more, you want to play more matches," Darcis said. "I was playing maybe the best tennis in my life here. Not to go on the court today, it's maybe the biggest disappointing thing I have to do."

John Isner, the 18th-seeded American, retired during his second-round match against Adrian Mannarino of France with a left knee injury after only two games.

Isner took a medical time out during the second game and a trainer taped the knee. But he was clearly hobbled and decided to quit after serving the first point in the third game.

The retirement came three years after Isner beat Nicolas Mahut 70-68 in the fifth set in a match that lasted more than 11 hours over three days. Now, Isner is out after one of the shortest matches in Wimbledon history.

"I always serve and land on my left leg, like I have done 20 million times playing this game, and this is the first time I just felt this sharp pain," he said. "It didn't pop. It just grabbed like really badly, and I knew I was in serious trouble then. I knew at that point it was not likely I was going to be able to play."

Isner said it appeared to be a tendon injury, not a major tear, and he does not expect to need surgery.

"I just can't bend my knee," he said. "I can walk as long as I keep it straight."

Away from the injury front, seven-time champion Roger Federer was to face Sergiy Stakhovsky on Centre Court, while 2012 U.S. Open champion and Wimbledon runner-up Andy Murray was placed on Court 1.