Federer and Djokovic call for rule change as retirements ruffle Wimbledon crowd

Roger Federer and Novak Djokovic called for Wimbledon to change its rules after both of their opponents retired on a disgruntled Centre Court.

Djokovic was leading Martin Klizan 6-3 2-0 when the Slovakian succumbed to a calf injury before Alexandr Dolgopolov pulled the plug in his first-round match at 6-3 3-0 down to Federer.