PREVIEW

(200121) -- MELBOURNE, Jan. 21, 2020 (Xinhua) -- Daniil Medvedev returns a shot during the men's singles first round match between Daniil Medvedev of Russia and Frances Tiafoe of the United States at 2020 Australian Open in Melbourne, Australia, Jan. 21, 2020. (Xinhua/Wang Jingqiang)