China's Duan Yingying hits a return during the women's singles first round match against Denmark's Wozniacki at the US Open tennis championships in New York, Aug. 27, 2013. Duan Yingying lost 0-2. (Xinhua/Wang Lei)

China's Duan Yingying reacts during the women's singles first round match against Denmark's Wozniacki at the US Open tennis championships in New York, Aug. 27, 2013. Duan Yingying lost 0-2. (Xinhua/Wang Lei)

China's Duan Yingying reacts during the women's singles first round match against Denmark's Wozniacki at the US Open tennis championships in New York, Aug. 27, 2013. Duan Yingying lost 0-2. (Xinhua/Wang Lei)

China's Duan Yingying hits a return during the women's singles first round match against Denmark's Wozniacki at the US Open tennis championships in New York, Aug. 27, 2013. Duan Yingying lost 0-2. (Xinhua/Wang Lei)