Stan Wawrinka of Switzerland hits the ball during the men's singles second round match against Steve Johnson of the United States at the Australian Open Tennis Championships in Melbourne, Australia, Jan. 18, 2017. Wawrinka won 3-0. (Xinhua/Bai Xue)
Stan Wawrinka of Switzerland hits the ball during the men's singles second round match against Steve Johnson of the United States at the Australian Open Tennis Championships in Melbourne, Australia, Jan. 18, 2017. Wawrinka won 3-0. (Xinhua/Bai Xue)