LOS ANGELES (AP) — The United States won back the Walker Cup from Britain and Ireland in an unprecedented runaway that atoned for a big loss two years ago.

Collin Morikawa, Doug Ghim and Maverick McNealy each went 4-0 — a first for a team in Walker Cup history — to lead the United States to a 19-7 victory Sunday in the biennial amateur matches at the super exclusive Los Angeles Country Club’s North Course.

Norman Xiong, at 18 the youngest player in the competition, came painfully close to also going 4-0 before halving his match with Scott Gregory. Xiong, one of three Southern Californians who had huge performances this weekend, had been up 2 with two holes to play before Gregory caught him.

It was a big turnaround from two years ago, when Britain and Ireland won 16 1/2-9 1/2 at Royal Lytham & St. Annes. The 19 points for the Americans matched the most ever in Walker Cup history. That came in 1993 when the United States won 19-5 at Interlachen.

It was special for Morikawa in helping the United States extend its lead to 36-9-1 in a series that dates to 1922.

Morikawa, who’s from La Canada Flintridge and plays at California, beat British Amateur champion Harry Ellis 2 and 1 to cap his perfect weekend.

“It’s something special and you can’t really explain what it is,” Morikawa said. “I wasn’t really nervous on the first tee, in the first shot for the U.S. on Saturday morning, but you just kind of are excited and thrilled that you can get out there and hit a tee ball for your country.”

Morikawa teamed with Xiong, who’s from Canyon Lake, to win foursomes matches Saturday and Sunday mornings. Both won their singles matches Saturday afternoon.

Morikawa was 2 down after three holes before winning four straight holes to take control. It helped, too, when Ellis bogeyed the par-3 11th.

“I’ve never really gone undefeated in one of these team events, and just to have some momentum to know that I can do it against these guys, these guys are the best players around the country and the entire world, really,” he said.

Morikawa and Xiong got the rout going Saturday morning when they beat…