World number two Victoria Azarenka has pulled out of Wimbledon with a knee injury.
The Belarusian was due to play Italy's Flavia Pennetta in the second round on Tuesday but withdrew before taking the court.
The Australian Open champion picked up a problem after slipping during her first-round win over Maria Joao Koehler on Monday.
Azarenka has reached the semi-finals at SW19 in the past two years.
