
Alexander Zverev of Germany serves during the men's singles second round match against Borna Coric of Croatia at the 2017 US Open in New York, the United States, Aug. 30, 2017. (Xinhua/Li Muzi)

Alexander Zverev of Germany serves during the men's singles second round match against Borna Coric of Croatia at the 2017 US Open in New York, the United States, Aug. 30, 2017. (Xinhua/Li Muzi)