Ostrava WTA results on Friday (x denotes seeded player): Quarter-finals Maria Sakkari (GRE) bt Ons Jabeur (TUN) 3-6, 6-3, 6-1 Victoria Azarenka (BLR x4) bt Elise Mertens (BEL x7) 6-4, 6-1 Aryna Sabalenka (BLR x3) bt Sara Sorribes Tormo (ESP) 0-6, 6-4, 6-0 Jennifer Brady (USA) bt Veronika Kudermetova (RUS) 6-7 (5/7), 6-3, 6-1 afp