ZHENGZHOU, China (AP) -- Three-time Grand Slam champion Angelique Kerber lost in the opening round of the Zhengzhou Open on Tuesday, falling to Alison Riske of the United States 5-7, 6-4, 7-6 (6).
Unseeded Kristina Mladenovic advanced, beating local wildcard Ying-Ying Duan 6-2, 6-3. Mladenovic finished with only 10 unforced errors while Duan had 25.
''It was very tricky conditions: It's super humid, and it's never easy to start a tournament,'' Mladenovic said. ''Every first round is difficult, and Ying-Ying, I've played her in the past and she's a very powerful player with a big serve.''
Mladenovic will next face another Frenchwoman, Caroline Garcia.
Two more French players advanced. Fiona Ferro beat Zhaoxuan Yang 6-2, 6-3, and Alize Cornet defeated Jia-Jing Lu 7-6 (1), 6-1.
Also, 2017 French Open champion Jelena Ostapenko beat You Xiaodi 6-3, 0-6, 6-2.
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