Tennis: Azarenka forced out of Wimbledon with injury

Victoria Azarenka during the 2016 French Open at Roland Garros. Photo / Getty Images

Former world number one Victoria Azarenka is out of Wimbledon with a knee injury.

Azarenka of Belarus had been seeded sixth at the championships, but had not played since retiring from a first-round match last month at the French Open.

She's reached the Wimbledon semi-finals twice and the quarter-finals on two occasions.