BERLIN, June 18 (Xinhua) -- China's tennis star Zheng Qinwen hit a season-high 23 aces to outplay former world No. 1 Naomi Osaka in the first round of the WTA 500 Berlin Open here on Tuesday.
The world No. 8 took 130 minutes to defeat Osaka in three sets, 6-4, 3-6, 6-3, improving her head-to-head record to 2-1.
The victory is Zheng's second of the season over Osaka after beating the Japanese on clay last
