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/Zhu Hongye)
Stan Wawrinka of Switzerland celebrates after winning his 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)
Roger Federer of Switzerland hits the ball during the men's singles first-round match against Jurgen Melzer of Austria at the Australian Open Tennis Championships in Melbourne, Australia, Jan. 16, 2017. Federer won 3-1. (Xinhua/Zhu Hongye)
Roger Federer of Switzerland hits the ball during the men's singles first-round match against Jurgen Melzer of Austria at the Australian Open Tennis Championships in Melbourne, Australia, Jan. 16, 2017. Federer won 3-1. (Xinhua/Zhu Hongye)
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)
Roger Federer of Switzerland hits the ball during the men's singles first-round match against Jurgen Melzer of Austria at the Australian Open Tennis Championships in Melbourne, Australia, Jan. 16, 2017. Federer won 3-1. (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/Zhu Hongye)
Roger Federer of Switzerland hits the ball during the men's singles first-round match against Jurgen Melzer of Austria at the Australian Open Tennis Championships in Melbourne, Australia, Jan. 16, 2017. Federer won 3-1. (Xinhua/Bai Xue)
