Women's singles No.2 seed Victoria Azarenka and Rafael Nadal's conqueror Steve Darcis are among four players who have withdrawn from Wimbledon with injuries here Wednesday.
Belgian Darcis did not even make it onto the court to play his second round men's singles match against Polish Lukasz Kubot because of a shoulder injury.
Azarenka had been scheduled to face Italy's Flavia Pennetta in the first match of Wednesday on Centre Court.
The Belarusian, who has reached the semifinals in her past two visits here, had fallen awkwardly in the second set of her first round match Monday against Maria Joao Koehler of Portugal. Despite being in pain, Azarenka hobbled to a 6-1, 6-2 victory.
However, she could not step onto the court Wednesday.
American John Isner, who tweaked his left knee in the opening game against France's Adrian Mannarino, retired with the score 1-1. The tall American started his match looking in prime form, winning the opening game in less than a minute. However, the World No.21 began clutching his left knee and minutes later after a medical timeout, retired.
Czech Republic's Radek Stepanek could not shake off a thigh problem and retired against Jerzy Janowicz.