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

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

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

"I would say (it's a) very black day," Cilic said of the rash of injury withdrawals. "The other days, other weeks, there were no pullouts. Everything just happened today."

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 Jamaica in 2010, was in tears after beating the former No. 1-ranked player.

"I cried like a little girl," said Brown, who has played mainly on the lower-tier challenger circuit in 2013 and had never won a match at Wimbledon until this year.

For Hewitt, who upset 11th-seeded Stanislas Wawrinka in the first round, it was a dispiriting departure from his 15th straight appearance at the All England Club. Asked if he would be back next year, he said, "Yeah, definitely. We'll see."

Another former top-ranked player, Caroline Wozniacki, is leaving the tournament early. The ninth-seeded Dane — whose right ankle was taped — slumped to a 6-2, 6-2 loss to 196th-ranked Czech qualifier Petra Cetkovska, continuing her disappointing run since finishing 2011 as No. 1.

In another women's match, Canadian teenager Eugenie Bouchard picked up the biggest victory of her career, beating 12th-seeded Ana Ivanovic, the 2008 French Open champion, 6-3, 6-3 to reach the third round. The 66th-ranked Bouchard, who is 19, won the girls' title at the All England Club a year ago.

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 five-time champion Serena 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."

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.

"After the match, a few hours after, I start to feel so much pain, I couldn't sleep that night," he said. "I saw the physio, the doctor, yesterday. They did a good job. It's a little bit better today. But no chance I can play. I cannot serve. It makes no sense to go on the court to withdraw after two games."

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."

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.

Isner, who was trying to reach the third round at Wimbledon for the first time, said he felt something in his knee when he landed on his left leg after hitting a serve on the third point of the match.

"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.

Maria Sharapova, the 2004 Wimbledon champ, was scheduled to play her second-round match on Court 2 against 131st-ranked qualifier Michelle Larcher de Brito of Portugal.