AUSTRALIAN OPEN ’20: Nadal, Djokovic, Federer still on top

              FILE - In this Sept. 8, 2019, file photo, Rafael Nadal, of Spain, returns a shot to Daniil Medvedev, of Russia, during the men's singles final of the U.S. Open tennis championships in New York. Nadal will compete in the Australian Open tennis tournament beginning Monday, Jan. 20, 2020. (AP Photo/Sarah Stier, File)

MELBOURNE, Australia (AP) — Men to watch at the Australian Open, where play begins Monday: