Unbeaten Tiger Woods and Matt Kuchar edged Japan's Hideki Matsuyama and Australian Adam Scott 1-up to give the United States a 10 1/2-6 1/2 lead over the Internationals on Saturday at the storm-hit Presidents Cup.
World number one Woods and Kuchar improved to 3-0 in the team golf showdown at Muirfield Village, where heavy rain drenched the course for a third day in a row, draining energy from every player.
"Tiger is honestly beat up. But Tiger is playing his tail off," US captain Fred Couples said. "He's a little sore and a little battered and this course, the ball is not rolling, it's playing much harder and much longer so it's tougher on everybody."
After splitting four foursomes matches ending Saturday morning following a Friday storm, the Americans went 4-1 in four-ball matches. Five more alternate-shot matches began on the soggy course with no hope to finish by dark.
"It's one thing to have rain delays but when you've got 36 holes in one day and you've got rain delays, that's a whole new story," Internationals captain Nick Price said.
"This is 36 holes of intense pressure for these guys. It's the end of the season and they are tired. I think they are doing phenomenally well. They've played their hearts out."
Woods, a 14-time major winner and US PGA Player of the Year after five wins this season, is a five-time winner of the Memorial, the US PGA event played at Muirfield Village, and Kuchar is the reigning Memorial champion.
Matsuyama, 21, birdied two of the first three holes for a 2-up lead. Woods answered with three birdies in a row to level the match.
Matsuyama sank a five-foot par putt to win the 10th but Woods responded with a birdie at 13 and Kuchar birdied 14 to put the US duo ahead.
Woods pumped his first in the fairway after putting his second shot four feet from the hole for a conceded eagle to win the par-5 15th for a 2-up edge.
"This guy is a horse. I was along for the ride for most of it," Kuchar said of Woods. "He played some incredible golf."
Matsuyama won the 16th with a 12-foot birdie but Kuchar birdied 18 to end the match.
"We made a little run and then Hideki made a bomb on 16 to make it a little interesting," said Woods, who has won a record 23 Presidents Cup matches.
The overall 7 1/2-3 1/2 US edge in four-ball marks the first time in 17 years of Ryder or Presidents Cup play that the Americans had the edge in that format.
Golfers were using lift, clean and place rules and at times playing in heavy downpours on a water-logged course.
Play was halted for more than an hour after a downpour left bunkers flooded, pools on greens and rivers in fairways.
"When you've got 36 holes in one day and you've got rain delays, that's a whole new story," Price said.
"This is 36 holes of intense pressure for these guys."
While course workers made the Jack Nicklaus-designed layout playable again, thunderstorms and up to three inches of rain are predicted Sunday, when 12 concluding singles matches are scheduled.
Reigning British Open champion Phil Mickelson and Keegan Bradley edged South African Ernie Els and Zimbabwe's Brendon de Jonge 2 and 1.
Two-down after seven holes, Mickelson birdied eight and Bradley birdied nine to level the match. Mickelson birdied 12th and 13th, Bradley's three-foot birdie putt won the par-5 15th and the US duo halved 17 to close out the win.
"We played so good," Bradley said. "We hung in there and we were able to turn it around. That was a big win for us."
Aussie Jason Day, a member at Muirfield Village, and Canada's Graham DeLaet beat Steve Stricker and Jordan Spieth 2-up.
Stricker sank a four-foot birdie putt to win the par-3 12th and equalize but DeLaet answered with a birdie at the par-3 16th and Day birdied 18 to seal victory.
Bill Haas and Webb Simpson never trailed in downing Argentina's Angel Cabrera and South African Branden Grace 4 and 3.
Hunter Mahan and Brandt Snedeker never trailed in a 2-up win over South Africans Charl Schwartzel and Louis Oosthuizen.