
Rafael Nadal of Spain serves during the men's singles fourth round match against Alexandr Dolgopolov of Ukraine at the 2017 U.S. Open in New York, the United States, Sept. 4, 2017. Rafael Nadal won 3-0 to enter the next round. (Xinhua/Qin Lang)

Rafael Nadal of Spain serves during the men's singles fourth round match against Alexandr Dolgopolov of Ukraine at the 2017 U.S. Open in New York, the United States, Sept. 4, 2017. Rafael Nadal won 3-0 to enter the next round. (Xinhua/Qin Lang)