Results from the WTA tournament in Saint Petersburg on Monday (x denotes seeding): 1st rd Maria Sakkari (GRE x6) bt Vitalia Diatchenko (RUS) 3-6, 6-4, 7-6 (7/3) Elena Rybakina (KAZ x8) bt Katerina Siniakova (CZE) 6-3, 6-4 Anastasia Potapova (RUS) bt Liudmila Samsonova (RUS) 6-2, 6-4 afp