Defending champion Coco Gauff was upset 6-4, 2-6, 6-4 by Yulia Putintseva in her opening match at the WTA Cincinnati Open on Thursday. World number two Gauff, who carried the flag for the US Olympic team in Paris, had beaten her Kazakh opponent in all three previous meetings. Gauff, who won last year’s US Open for her first Grand Slam title, won at Cincinnati last year, becoming the event’s youngest champion at age 19. Her next match is set to be in defending her title at the US Open, which starts on August 26.