
Spain's Rafael Nadal serves during the men's singles quarterfinal of the China Open tennis tournament against Jack Sock of the United States in Beijing, China, Oct. 9, 2015. Nadal won 2-1 and advanced to the semifinal. (Xinhua/Li Wen)

Spain's Rafael Nadal serves during the men's singles quarterfinal of the China Open tennis tournament against Jack Sock of the United States in Beijing, China, Oct. 9, 2015. Nadal won 2-1 and advanced to the semifinal. (Xinhua/Li Wen)