Los Angeles - Coco Vandeweghe defeated Andrea Petkovic on Sunday to deliver the killing blow in a nightmare Fed Cup tie for Germany that had kicked off with a first-day national anthem gaffe.
Petkovic and her team-mates were angered on Saturday when an American soloist sang an old version of the German anthem that begins with a stanza considered overtly nationalist - "Deutschland, Deutschland ueber alles" - a reference to German supremacy.
Singing that version is unwelcome in Germany because of its strong links to the Nazi era, with only the third stanza of the old anthem now used.
"I have never felt so disrespected in my life," Petkovic said on Saturday. "It was an absolute effrontery and insolence of the very worst kind."
Things would get no better for Germany on the court in Maui, Hawaii.
Petkovic, a 12-time Fed Cup singles winner, lost to Alison Riske 7-6 (12/10), 6-2 in Saturday's only completed match.
The US women took a 2-0 lead in the best-of-five tie when Julia Georges, who was in tears after the anthem error, retired on Sunday with a knee injury in a rain-disrupted match with Vandeweghe leading 6-3, 3-1.
Georges was hurt slipping on a rain-slicked baseline on the last point played on Saturday.
Petkovic was up again on Sunday with the tie on the line, taking on shock Australian Open semi-finalist Vandeweghe.
Petkovic broke Vandeweghe in three of her first four service games to take the first set 6-3, and was up 4-2 in the second when the American took a medical timeout for heat illness.
From there it was all Vandeweghe - she won the next 10 games to win the match 3-6, 6-4, 6-0 and put the United States into a semi-final tie in April with defending champions the Czech Republic, who beat Spain 3-2.
Petkovic, irked by an extended break allotted to Vandeweghe at the end of the second set, couldn't regain her focus.
She finished with 11 double faults, including two in the final game of the match.
She was then left to stand and watch as Vandeweghe celebrated with her team-mates before belatedly shaking hands with her foe.
Even a meaningless doubles rubber played after the tie was decided was a disaster for Germany, as Laura Siegemund and Carina Witthoeft retired while trailing Bethanie Mattek-Sands and Shelby Rogers 4-1 because of Siegemund's left arm injury.
"Honestly, it's been a really tough week for us," said Petkovic, who took to Twitter on Sunday to elaborate on her feelings about the anthem mix-up.
"We were mainly (stunned) and did not know how we react. We feared the whole thing could fall back on us," Petkovic said.
"It is not the worst thing which happened to me in life. But it is the worst thing which happened to me in my Fed Cup life ever."
SPECIAL MOMENT RUINED
Germany captain Barbara Rittner said she had even pondered snatching the microphone from the singer.
"I could have cried, because it is always a special moment, which gives you goosebumps, when you hear the anthem being played," Rittner said.
The president of the US Tennis Association, Katrina Adams, immediately apologised to Rittner in person and promised to investigate.
"The USTA extends a sincere apology to the German Fed Cup team & fans 4 the outdated National Anthem," the US Tennis Association tweeted. "This mistake will not occur again."
Collated Fed Cup World Group I results (start times in GMT):
At Ostrava (Indoor, hard)
Czech Republic 3 Spain 2
Garbine Muguruza (ESP) bt Barbora Strycova (CZE) 6-0, 3-6, 6-1
Karolina Pliskova (CZE) bt Lara Arruabarrena (ESP) 6-4, 7-5
Karolina Pliskova (CZE) bt Garbine Muguruza (ESP) 6-2, 6-2
Barbora Strycova (CZE) bt Lara Arruabarrena (ESP) 6-4, 6-4
Sara Sorribes Tormo/Maria Jose Martinez Sanchez (ESP) bt Katerina Siniakova/Lucie Safarova (CZE) 6-3, 4-6, 10-7
At Maui, Hawaii (Outdoor, hard)
United States 4 Germany 0
Alison Riske (USA) bt Andrea Petkovic (GER) 7-6 (12/10), 6-2
CoCo Vandeweghe (USA) bt Julia Goerges (GER) 6-3, 3-1, retired (match continued from Saturday)
CoCo Vandeweghe (USA) bt Andrea Petkovic (GER) 3-6, 6-4, 6-0
Bethanie Mattek-Sands/Shelby Rogers (USA) bt Laura Siegemund/Carina Witthoeft (GER) 4-1, retired
Alison Riske (USA) v Julia Goerges (GER) -- not played
At Minsk (Indoor, hard)
Belarus 4 Netherlands 1
Aliaksandra Sasnovich (BLR) bt Michaella Krajicek (NED) 4-6, 6-3, 6-2
Kiki Bertens (NED) bt Aryna Sabalenka (BLR) 3-6, 7-6 (8/6), 6-4
Aliaksandra Sasnovich (BLR) bt Kiki Bertens (NED) 6-3, 6-4
Aryna Sabalenka (BLR) bt Michaella Krajicek (NED) 7-6 (7/5), 6-4
Olga Govortsova/Vera Lapko (BLR) bt Cindy Burger/Arantxa Rus (NED) 6-4, 6-2
At Geneva (Indoor, hard)
Switzerland 4 France 1
Timea Bacsinszky (SUI) bt Alize Cornet (FRA) 7-5, 6-4
Kristina Mladenovic (FRA) bt Belinda Bencic (SUI) 6-3, 6-4
Timea Bacsinszky (SUI) bt Kristina Mladenovic (FRA) 7-6 (7/4), 4-6, 7-5
Belinda Bencic (SUI) bt Pauline Parmentier (FRA) 6-3, 6-4
Martina Hingis/Timea Bacsinszky (SUI) bt Amandine Hesse/Kristina Mladenovic (FRA) 6-4, 6-4