Stan Wawrinka plays tennis with a ballboy during delay
{{#rendered}} {{/rendered}}Defending French Open champion Stan Wawrinka advanced to the quarterfinals with a four-set victory over Viktor Troicki Sunday at Roland Garros, a match which was shortly delayed two hours in when Troicki needed medical treatment. To pass the time, Wawrinka invited one of the ballkids to play on Court Philippe-Chatrier.