Slovakia reached the last eight of the Billie Jean King Cup final with a 2-1 comeback victory over 18-time champions USA.
Taylor Townsend gave the United States the lead with a 7-5, 6-4 victory over 17-year-old Renata Jamrichova in the first singles match.
But Slovakian Rebecca Sramkova, ranked 43rd, caused an upset when she beat world number 11 Danielle Collins 6-2 7-5, breaking the tie and forcing a decider in doubles.
Tereza Mihalikova and Viktoria Hruncakova teamed up to defeat Townsend and Ashlyn Krueger 6-3, 3-6, 10-8 set up the quarter-final game for Australia, who received a bye in the first round.
Previously, Japan became the first team to claim a first-round win, beating Romania 2-1 to book their place in the last eight where they will face 2023 runners-up Italy.
The opening match of the tournament between Spain and Poland was postponed on Wednesday due to a severe weather warning.
It has been moved to Friday, with the game starting at 09:00 GMT before Great Britain face Germany from 4:00 p.m.