
Stan Wawrinka of Switzerland returns the ball during the men's singles first round match against Martin Klizan of Slovakia at the Australian Open Tennis Championships in Melbourne, Australia, Jan. 16, 2017. Wawrinka won 3-2. (Xinhua/Bai Xue)

Stan Wawrinka of Switzerland returns the ball during the men's singles first round match against Martin Klizan of Slovakia at the Australian Open Tennis Championships in Melbourne, Australia, Jan. 16, 2017. Wawrinka won 3-2. (Xinhua/Bai Xue)