Four-time defending champion Caroline Wozniacki advanced to the semi-finals of the WTA New Haven Open on Thursday but a slight right knee injury put a damper on the celebration. “I decided straight away after I felt it,” she said. “I played one more point and decided I needed to see the trainer because I felt a sharp pain in there. I needed to treat it.” The Danish third seed, who is set to be the eighth seed in next week’s US Open, defeated Slovakia’s Dominika Cibulkova 6-2, 6-1 in the quarter-finals and remained unbeaten at New Haven, improving to 20-0. Wozniacki is scheduled to face Russian seventh seed Maria Kirilenko, who beat Olga Govortsova of Belarus 6-1, 6-2 in another quarter-final on Thursday. From gulftoday