Serbia's Djokovic wins his third U.S. Open men's singles title

Juan Martin del Potro of Argentina hits a return during the men's singles final match against Novak Djokovic of Serbia at the 2018 US Open tennis tournament in New York, the United States, Sept. 9, 2018. Djokovic claimed the title by defeating Juan Martin del Potro of Argentina with 3-0 in the final. (Xinhua/Wang Ying)