Results from the WTA tournament in Doha on Thursday (x denotes seeding): Quarter-finals Ashleigh Barty (AUS x1) bt Garbiñe Muguruza (ESP x11) 6-1, 6-7 (4/7), 6-2 Petra Kvitova (CZE x8) bt Ons Jabeur (TUN) 7-6 (7/2), 7-6 (7/4) Svetlana Kuznetsova (RUS) bt Belinda Bencic (SUI x4) 6-4, 6-4 Aryna Sabalenka (BLR x9) bt Zheng Saisai (CHN) 3-6, 7-6 (7/2), 6-3 afp