Wozniacki calls for introduction of shot clocks

FORMER world No1 Caroline Wozniacki has called on tennis authorities to get tough on time-wasters following her surprise fourth-round exit in straight sets to Barbora Zahlavova-Strycova.

With top two seeds Serena Williams and Li Na already out, 2012 finalist Agnieszka Radwanska and former world No1 Ana Ivanovic joined Wozniacki on the scrapheap on a rain-disrupted day at Wimbledon.

An idea of clocks being installed on court to ensure the permitted 20-second time limit between shots is adhered to was first raised by Roger Federer and Wozniacki echoed the 17-time grand slam champion’s sentiment after a frustrating 6-2, 7-5 defeat.

“I wouldn’t mind [a clock], I think that’s fine,” said the No16 seed, who has never been past the fourth round at Wimbledon.

“I thought she [Zahlavova-Strycova] was very slow, but I guess the referee, she has the time on it. I guess if she’s within the time it’s okay. It’s up to the umpire to say if she is or not.”

Ninth seed John Isner suffered defeat to Spain’s Felciano Lopez and – with teenager Madison Keys unable to resume her third round match with Kazakhstan’s Yaroslava Shvedova, which began on Saturday, due to a thigh injury – America has no male or female representation in the last 16 stage at Wimbledon for the first time since 1911.

No1 seed Novak Djokovic reached his 21st consecutive grand slam quarter-final with victory over France’s Jo-Wilfried Tsonga, himself twice a semi-finalist at SW19.

The Serbian star won 6-3, 6-4, 7-6 under the Centre Court roof and later urged Wimbledon to drop its tradition of no play on middle Sunday to avoid schedule congestion in future.

Australian Open champion Stan Wawrinka won through in straight sets, while there were victories too for Andy Murray’s next opponent Grigor Dimitrov, Japan’s Kei Nishikori and Marin Cilic, seeded 26th.

Last year’s runner-up Sabine Lisicki beat Ivanovic, while 20-year-old Eugenie Bouchard and 2011 champion Petra Kvitova also progressed.