The German was irritated by fans walking around during play.
The world No. 8 is still hoping to qualify for the WTA Finals.
The world No. 1 routed Simone Bolelli, 6-1, 6-1.
Stan will face Tatsuma Ito, who beat him in Tokyo last year.
The world No. 7 hasn't won a major or Masters tournament this year.
Serena has already given us more than enough drama, and excellence, in 2015.
A look ahead at four events, including a deep WTA draw in Wuhan.
Jelena Jankovic and Ana Ivanovic continue to fascinate us after all these years.
Examining Rafael Nadal as his disappointing season winds down.