Romania upset defending champion Czech Republic 3-2 to advance to the semifinals of the Fed Cup on Sunday, along with France, Belarus and Australia.
Romania reached the semifinals for the first time after its first victory against the Czechs, who won six titles in the last eight years.
Irina-Camelia Begu and Monica Niculescu teamed up to clinch the best-of-five contest with a 6-7 (2), 6-4, 6-4 win over Czech pair Katerina Siniakova and Barbora Krejcikova in the doubles.
Romania took a 2-1 lead on an indoor hard-court in Ostrava after Simona Halep beat Karolina Pliskova 6-4, 5-7, 6-4 in a reverse singles featuring two former top-ranked players. Halep improved her record against Pliskova to 7-2 to put Romania one win from advancing.
Earlier, Barty beat Madison Keys 6-4, 6-1 to give Australia a 2-1 lead. Collins, who reached her first Grand Slam semifinal at the Australian Open last month, made it 2-2 after a 6-1, 3-6, 6-2 victory over Daria Gavrilova.
The Australians will next play Belarus, which lost the 2017 final to the U.S., in April. Belarus dominated at Braunschweig, with Aryna Sabalenka cruising past Laura Siegemund 6-1, 6-1 to give her country an insurmountable 3-0 lead over host Germany on an indoor hard court.
In the final doubles match, Victoria Azarenka teamed up with Lidziya Marozava to beat Mona Barthel and Anna-Lena Groenefeld 6-1, 0-6, 11-9 to win 4-0 overall.