Cole Hammer finally got a point with the shortest match. John Pak completed a perfect week. John Augenstein delivered the clinching point.
And for the first time in 12 years, the Americans celebrated a Walker Cup victory away from home.
Facing a two-point deficit at the start of Sunday, the Americans picked up a point in morning foursomes and then overwhelmed Great Britain & Ireland by taking eight of 10 singles matches for a 15 1/2-10 1/2 victory at Royal Liverpool.
Team USA won the Walker Cup for the second straight time, and the first time overseas since winning at Royal County Down in 2007.
"They've got a great memory now," U.S. captain Nathaniel Crosby said.
The Americans won two of three matches and tied the other in foursomes. GB&I quickly picked up a point in singles when Sandy Scott beat Brandon Wu, the Stanford grad's first loss of the week.
The rest was all U.S. red.
Hammer was 3 up through six holes on his way to a 6-and-5 victory over Conor Purcell. Pak made it 3-0 for the week with a 2-and-1 victory over Euan Walker. Augenstein, the U.S. Amateur runner-up, began the Walker Cup with the opening tee shot Saturday and officially clinched it Sunday with his 4-and-3 win over Thomas Plumb.
The Americans also won eight of 10 points in Sunday singles two years ago when they won 19-7 at Los Angeles Country Club. Their victory at Royal Liverpool was their widest margin away from home since a nine-point victory at Sunningdale in 1987.
The U.S. team increased the series lead to 37-9-1. The Walker Cup will be held at Seminole Golf Club in Florida in 2021.