The Czech Republic took a 2-0 lead on home soil in the Fed Cup final against defending champions United States.
Barbora Strycova and Katerina Siniakova both won their matches against Sofia Kenin and Alison Riske respectively to put the hosts one point from victory.
Strycova, playing in the last Fed Cup tie, went a set down in Prague to Kenin but won 6-7 (5-7) 6-1 6-4.
Siniakova had a more straightforward victory as she beat Riske by 6-3 7-6 (7-2).
Two singles matches and a doubles contest are scheduled to take place on Sunday, with the Czech Republic trying to secure a sixth Fed Cup title in eight years.