Novak Djokovic beats Kei Nishikori 3-0 at 2018 US Open tennis tournament

Novak Djokovic of Serbia serves during the men's singles semifinal match against Kei Nishikori of Japan at the 2018 US Open tennis tournament in New York, the United States, Sept. 7, 2018. Novak Djokovic won 3-0. (Xinhua/Liu Jie)