Germany's player Angelique Kerber (R) shakes hands with the United States' player Madison Keys after the WTA Finals round robin match at Singapore Indoor Stadium, Oct. 27, 2016. Kerber won 2-0. (Xinhua/Then Chih Wey)
Germany's player Angelique Kerber celebrates after winning the WTA Finals round robin match against the United States' player Madison Keys at Singapore Indoor Stadium, Oct. 27, 2016. Kerber won 2-0. (Xinhua/Then Chih Wey)
Germany's player Angelique Kerber returns the ball during the WTA Finals round robin match against the United States' player Madison Keys at Singapore Indoor Stadium, Oct. 27, 2016. Kerber won 2-0. (Xinhua/Then Chih Wey)
Germany's player Angelique Kerber returns the ball during the WTA Finals round robin match against the United States' player Madison Keys at Singapore Indoor Stadium, Oct. 27, 2016. Kerber won 2-0. (Xinhua/Then Chih Wey)
The United States' player Madison Keys returns the ball during the WTA Finals round robin match against Germany's player Angelique Kerber at Singapore Indoor Stadium, Oct. 27, 2016. Keys lost 0-2.(Xinhua/Then Chih Wey)
