
Angelique Kerber of Germany hits a return during the women's singles first round match against Naomi Osaka of Japan at the 2017 US Open tennis tournament in New York, the United States, Aug. 29, 2017. (Xinhua/Wang Ying)

Angelique Kerber of Germany hits a return during the women's singles first round match against Naomi Osaka of Japan at the 2017 US Open tennis tournament in New York, the United States, Aug. 29, 2017. (Xinhua/Wang Ying)