Sanchez Vicario has a combined 6 wins over Evert, Graf, and Seles in slams which is pretty good too. 4 of them came vs Graf, she was Seles's little lapdog but didnt get to play Seles during her peak period of 94-early 96. Evert she barely got to play but a #4 seeded Evert got spanked by unseeded 15 year old Sanchez at the 88 French which was an impressive performance.
Comparing Sanchez to Mandlikova is funny since Hana is about 5 times more talented, but about 5 times weaker in work ethic, consistency, mental strength. So hard to say who is better. I would probably say Hana since Sanchez's game was only effective against Graf. She was useless against Seles, Hingis, and even a fairly old (before she became really old) Navratilova. Hana only seemed fairly useless against Graf but dangerous for anyone else she played (I dont count Seles who she played twice in her final year and got walloped by).