Top seed Flavia Pennetta lost in the first round of the Tianjin Open against Lyudmyla Kichenok in China on Tuesday.
The unseeded Kichenok of Ukraine beat the Italian and US Open Champion in straight sets, winning 6-3, 7-5 in one hour and 28 minutes, and second seed Agnieszka Radwanska of Poland cruised past Ukraine's Olga Savchuk 6-1, 6-0.
In other singles matches, Czech Republic third seed Karolina Pliskova beat Kristina Kucova of Slovakia 3-6, 6-3, 7-5 in just over two hours while Poland's Urszula Radwanska had little trouble getting past Nadiia Kichenok of Ukraine 6-4, 6-0.
Serbia's Bojana Jovanovski won a three-setter against Ons Jabeur of Tunisia 6-7(1), 7-6(4), 6-1 and China's Duan Yingying won in straights sets against Nicole Vaidisova of Czech Republic 6-3, 6-3.
Danka Kovinic of Montenegro comfortably beat Ukraine's Kateryna Bondarenko 6-4, 6-1 and Hungary's Timea Babos was way too good for Alla Kudryavtseva of Russia, winning 6-0, 6-1.%u200B