LONDON -- Seven players were knocked out of Wimbledon on Wednesday by withdrawals or mid-match retirements, believed to be the most in one day at a Grand Slam tournament in the 45-year Open era.
The 39th-ranked Gulbis was leading the second-round match 3-6, 6-3, 6-3 when Tsonga quit. Tsonga was the runner-up at the 2008 Australian Open and a semifinalist at the All England Club each of the past two years.
Following the second set, Tsonga sat on the grass while a trainer wrapped tape below his left knee.
Among the other men's players bowing out due to injuries Wednesday was the Belgian who stunned Rafael Nadal in the first round and the American who won the longest match in tennis history here three years ago.
Steve Darcis, who beat two-time champion Nadal in straight sets on Monday in one of Wimbledon's greatest upsets, pulled out on Wednesday because of a right shoulder injury.
The 135th-ranked Darcis withdrew just hours before he was scheduled to play Lukasz Kubot of Poland.
On the women's side, second-seeded Victoria Azarenka withdrew with a knee injury.
The International Tennis Federation said it believed the previous high total for one day at a major tournament was five, which happened on the first day of competition at Wimbledon last year, June 25.
"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."
Isner took a medical timeout 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.
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."
Darcis 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."