Results from the WTA tournament in Saint Petersburg on Friday (x denotes seeding): Quarter finals Maria Sakkari (GRE x6) bt Belinda Bencic (SUI x1) 2-6, 6-4, 6-3 Elena Rybakina (KAZ x8) bt Océane Dodin (FRA) 6-7 (5/7), 7-5, 6-2 Ekaterina Alexandrova (RUS) bt Petra Kvitova (CZE x3) retired Kiki Bertens (NED x2) bt Anastasia Potapova (RUS) 6-4, 7-6 (7/3) afp