Trailing by a point after the morning foursomes, the USA appeared sluggish.
But following the afternoon, the scoreboard was awash with red.
The U.S. settled down on Friday afternoon, pulling away with a record-setting fourball performance.
The United States swept the afternoon fourball matches to take a 5 1/2-2 1/2 lead at Des Moines Golf and Country Club.
Lizette Salas and U.S. newcomer Danielle Kang each won two matches, teaming to beat Carlota Ciganda and Caroline Masson 1 up for the Americans’ lone full point in the morning foursomes, then leading the U.S. to its first ever fourball sweep in the afternoon.
“This is the history we really don’t want. We want the history on Sunday night. We want the Cup,” U.S. captain Juli Inkster said.
“We’ve got a lot of work (ahead). I know (European captain) Annika (Sorenstam) is going to get that team fired up.”
Salas and rookie Angel Yin routed Ciganda and Emily Pedersen 6 and 5, and Kang and Michelle Wie topped Madelene Sagstrom and Jodi Ewart Shadoff 3 and 1.
In the other fourball matches, Brittany Lincicome and Brittany Lang beat Masson and Florentyna Parker 3 and 2, and Stacy Lewis and Gerina Piller edged Charley Hull and Georgia Hall 2 and 1.
In the morning foursomes, Americans Cristie Kerr and Lexi Thompson rallied to halve with Hull and Mel Reid. For Europe, Hall and Anna Nordqvist beat Paula Creamer and Austin Ernst 3 and 1, and Karine Icher and Catriona Matthew topped Lewis and Piller 1 up.
The 6-and-5 win was the second-largest in Solheim history.
“Everything kind of fell together,” Salas said.
After more foursomes and fourballs today, the event will closes with 12 singles matches Sunday.