Roger Federer of Switzerland serves the ball during the men's singles 4th round match against Stefanos Tsitsipas of Greece at the Australian Open in Melbourne, Australia, Jan. 20, 2019. (Xinhua/Bai Xuefei)
In pics: men's singles 4th round match at Australian Open
Source: Xinhua| 2019-01-20 18:57:53|Editor: mym
