:Underdogs Slovakia pulled off a stunning 2-1 win over the United States at the Billie Jean King Cup in Prague on Tuesday.
Even without the services of their top-four players, Danielle Collins and Shelby Rogers had been expected to steer the U.S. to victory considering the highest ranked player in the Slovakian camp was world number 83 Anna Karolína Schmiedlova.
However, after the two teams split the singles matches, the Slovak pairing of Viktoria Kuzmova and Tereza Mihalikova displayed nerves of steel to beat Caroline Dolehide and Coco Vandeweghe in the doubles 6-2 6-7(5) 12-10.
"I think for a small country like Slovakia, it's a really big result to beat USA in a competition like this, so I'm really proud of my girls," said captain Matej Liptak.
The 18-times champion Americans will have to beat Group C rivals Spain to have any chance of progressing to the semi-finals.
Earlier, Australian Daria Gavrilova felt like she had finally been set free when she marked her return to competitive action with a 6-4 1-6 6-4 win over Belgian Greet Minnen.
It was 27-year-old's first professional match since February and helped her country to a 2-1 upset of the Belgians after world number 131 Storm Sanders stunned Elise Mertens 3-6 7-6(5) 6-0 in her first match in the competition.
Mertens and Minnen paired up to win the doubles rubber to keep alive Belgium's hopes of progressing from Group B.
Germany have no such hopes following their second defeat in Group D, a 3-0 loss to Switzerland sending the twice champions out of the tournament.
The Russian Tennis Federation team also put paid to Canada's hopes of advancement from Group A after Daria Kasatkina and Anastasia Pavlyuchenkova won singles matches in another 3-0 sweep.
Former world number 20 Gavrilova has dropped down to 412th in the rankings after spending most of 2021 locked down in Melbourne due to the COVID-19 pandemic, while undergoing rehabilitation after an Achilles surgery.
In the absence of world number one Ash Barty, who pulled out of the event due to COVID-19 restrictions in Australia and to prepare for the next season, the 2019 runner-ups heavily depended on the 43rd-ranked Ajla Tomljanovic in Prague.
But with Tomljanovic forced to pull out from Tuesday's tie due to illness, the opportunity fell on Gavrilova to play the opening singles against Minnen, who came into the contest having won her singles rubber on Monday against Belarus.
"It was a really hard decision for our captain and the coaching team to make," Gavrilova said. "I think because they trusted and picked me and I had the belief, it all paid off.
"I think I'm probably here with the most motivation out of anyone in Prague, because I haven't played a match since February and everyone has had a long year."
(Reporting by Sudipto Ganguly in Mumbai, additional reporting by Philip O'Connor in Stockholm and Nick Mulvenney; editing by Christian Radnedge and Michael Perry)