Results from the WTA tournament in Berlin on Friday (x denotes seeding): Quarter-finals Liudmila Samsonova (RUS) bt Madison Keys (USA) 7-6 (7/4), 2-6, 7-6 (7/0) Victoria Azarenka (BLR x7) bt Jessica Pegula (USA) 6-2, 5-7, 6-4 Alize Cornet (FRA) bt Garbine Muguruza (ESP x6) 4-6, 6-3, 7-6 (7/5) Belinda Bencic (SUI x5) bt Ekaterina Alexandrova (RUS) 6-4, 4-6, 7-6 (7/4) afp