Players were in tears after controversy on the 17th green helped holders Europe take a 10-6 lead at the Solheim Cup.
Europe's Charley Hull and fourball partner Suzann Pettersen beat Alison Lee and Brittany Lincicome, of the United States, on Sunday after Lee picked up her ball.
Lee, 20, thought an 18-inch putt had been conceded as Hull had walked away.
But Pettersen said they had not conceded and the hole went to Europe who won two up on the 18th.
Both Hull and Lee, playing in her first Solheim Cup, had to be consoled by team officials amid claims Europe had broken the game's moral code by not conceding from such a short distance.
Four-time major winner Laura Davies blamed Norwegian Pettersen, 34, and said England's Hull, 19, was not at fault.
The Hall of Fame member told Sky Sports: "I am disgusted. Suzann has let herself and her team down."
|Analysis by BBC Sport's Iain Carter|
|"The rulebook was followed on the 17th green but the spirit of what happened was disappointing. There was fault on both sides.|
|"The putt was only eighteen inches and Europe profited from nothing more than a breakdown in communication.|
|"Had Europe played to the spirit of the game rather than the letter of the law they would still have enjoyed a healthy lead and a controversy that threatens to overshadow the match would have been avoided."|
US captain Juli Inkster thought Europe's action was "disrespectful".
She added: "I couldn't believe it. I saw Suzann walk away. You don't do that to your peers.
"I expected Carin (Koch, Europe captain) to do something afterwards but she didn't."
Koch said it was Lee's mistake, adding: "Our team didn't concede the putt. She picked it up. It broke the rules.
"We considered changing the outcome but we would not have given the putt. They would have made her putt it. So, no.
"We all feel bad for Alison but she made a mistake."
Europe went into Sunday's singles in a strong position after Karine Icher and Catriona Matthew birdied the last two holes of their fourball to beat Lizette Salas and Brittany Lang 2&1.
Americans Stacy Lewis and Gerina Piller won 1 up against Caroline Masson and Caroline Hedwall.
American pair Lexi Thompson and Cristie Kerr beat Spain's Azahara Munoz and Carlota Ciganda 3&2 in the only match completed on Saturday afternoon.
The 12 singles matches were starting immediately after the completion of the fourballs.
Europe need four more points to win the women's equivalent of the Ryder Cup for a third successive year, while the US need to reach a total of 14.5 points to regain the trophy.
Singles pairings: Ciganda v Thompson, Matthew v Pressel, Icher v Lincicome, Reid v Lang, Nocera v Lee, Masson v Piller, Nordqvist v Lewis, Munoz v Salas, Pettersen v Stanford, Hull v Kerr, Hedwall v Wie, Gal v Paula Creamer.
|Reid & Ciganda||Europe won 4&3||Lee & Wie|
|Hull & Pettersen||Europe win 1 up||Pressel & Creamer|
|Gal & Matthew||Europe win 1 up||Stanford & Lincicome|
|Nordqvist & Hedwall||US won 5&4||Lewis & Piller|
|Munoz & Ciganda||US won 3&2||Thompson & Kerr|
|Icher & Matthew||Europe win 2&1||Salas & Lang|
|Pettersen & Hull||Europe win 2 up||Lee & Lincicome|
|Masson & Hedwell||US win 1 up||Lewis & Piller|
Europe: Carlota Ciganda, Sandra Gal, Caroline Hedwall, Charley Hull, Karine Icher, Caroline Masson, Catriona Matthew, Azahara Munoz, Gwladys Nocera, Anna Nordqvist, Suzann Pettersen, Melissa Reid.
Captain: Carin Koch
United States: Paula Creamer, Cristie Kerr, Brittany Lang, Alison Lee, Stacy Lewis, Brittany Lincicome, Gerina Piller, Morgan Pressel, Lizette Salas, Angela Stanford, Lexi Thompson, Michelle Wie.
Captain: Juli Inkster