Argentine Federico Delbonis loses in the semi-finals of the German Tennis Championships . Federer beaten by world No.114 Roger Federer in straight sets . The German 17-time grand slam winner is trialling a new racquet with a larger frame . Wimbledon said early Federer exit was a good time to make the switch .
Roger Federer loses in the semi-finals of the German Tennis Championships . Federer beaten by world No.114 Argentine Federico Delbonis in straight sets . The Swiss 17-time grand slam winner is trialling a new racquet with a larger frame . Federer said early Wimbledon exit was a good time to make the switch .