Results at the WTA Bad Homburg grass court tournament on Friday (x denotes seeded player): Quarter finals Petra Kvitova (CZE x1) bt Nadia Podoroska (ARG x5) 6-3, 7-6 (12/10) Angelique Kerber (GER x4) bt Amanda Anisimova (USA) 2-6, 6-3, 6-3 Katerina Siniaková (CZE) bt Laura Siegemund (GER x8) 7-5, 6-4 afp