The Czechs can clinch their second consecutive Fed Cup Sunday with a victory in the reverse singles competition.
Safarova upended former world No. 1 Ana Ivanovic 6-4, 6-3 Saturday and Kvitova dispatched Jelena Jankovic 6-4, 6-1.
Kvitova, who won nine games in a row in her Saturday match, will face Ivanovic in Sunday's first match.
Sunday's doubles competition, if needed, would pit Andrea Hlavackova and Lucie Hradecka against Serbia's Bojana Jovanovski and Aleksandra Krunic.