The United States maintained their one-point lead over the International team in the Presidents Cup at 9 1/2 to 8 1/2 after the two sides picked up four points apiece in Incheon on Saturday.
Jordan Spieth and Patrick Reed's 3&2 win over Australia's Jason Day and South Africa's Charl Schwartzel at the conclusion of the afternoon fourball session put the Americans back in front.
Spieth turned the contest around with a run of three straight birdies from the seventh hole to go two up before a birdie from Reed on the 11th and Spieth again on the 12th put them all but out of sight.
It was Spieth's second win of the day after his earlier foursomes success alongside Dustin Johnson.
The teams took two wins each in the fourballs, with South African pair Louis Oosthuizen and Branden Grace beating JB Holmes and Bubba Watson, Phil Mickelson and Zach Johnson defeating Australia's Adam Scott and India's Anirban Lahiri 3&2 and, most impressively, South Korean home favourite Bae Sang-moon and Japan's Hideki Matsuyama thrashing Jimmy Walker and Chris Kirk 6&5.
Bae, whose 12-foot birdie putt to win his fourball clash helped the International team reduce the US lead on Friday, shot another three birdies, in succession from the seventh, while Matsuyama contributed three more.
In the morning foursomes, Oosthuizen and Grace were 3&2 winners over Reed and Rickie Fowler, while the matches which featured Watson and Holmes against Scott and Australia's Marc Leishman on the one hand and Bill Haas and Matt Kuchar versus Bae and Matsuyama on the other were both halved.
In the match between Spieth and Dustin Johnson and Day and Schwartzel the International pair led by three after the front nine, but the Americans responded to take the point with a par on the par-five 18th as their opponents could only make bogey.
