WTA Ostrava tournament results on Tuesday (x denotes seeding): 1st round Ons Jabeur (TUN) bt Barbora Strycova (CZE) 6-2, 6-2 Karolina Muchova (CZE) bt Shuai Zhang (CHN) 6-1, 6-1 Cori Gauff (USA) bt Katerina Siniakova (CZE) 7-5, 6-4 Darya Kasatkina (RUS) bt Elena Rybakina (KAZ x6) 6-2, 3-6, 6-3 Jennifer Brady (USA) bt Dayana Yastremska (UKR) 3-6, 7-6 (8/6), 6-1 Veronika Kudermetova (RUS) bt Donna Vekic (CRO) 6-2, 6-4 afp