Incheon - World No 1 Jordan Spieth holed two crucial, knee-trembling putts on the final two holes to maintain the US team's slender one-point lead after Saturday's morning foursomes in the Presidents Cup.
Spieth, with partner Dustin Johnson, was up against the man he battled for supremacy in Majors all season, Jason Day, who was teamed with Charl Schwartzel.
Once again it was the young Texan who emerged victorious, as he had in the US Masters and US Open this year, while Day beat Spieth to win the US PGA Championship.
Spieth and Johnson were down from the fourth hole, three down at the turn and one down with two to play at the Jack Nicklaus Golf Club in Incheon, South Korea.
But nerveless Spieth rolled in a seven-footer for a birdie to square the match and then repeated the feat for a winning par at the 18th.
It was a crucial turnaround after the US had lost one and halved two matches in the morning. It meant they went into the afternoon fourballs leading 7.5-6.5 after sharing the foursomes 2-2.
Spieth may have looked a picture of calmness as he stood over the putt to win the match, but he revealed straight after he was anything but serene inside.
"Your blood is running, it's running through your hands. You know it's there," he said.
"Just looking at the spot just in front of the ball allows me to get over the tension in my hand and make a nice, solid stroke over that point.
"That was a great fight. And it was a huge point in the Presidents Cup."
Earlier Branden Grace and Louis Oosthuizen continued their perfect run this week with a third win in a row, 3 and 2, over Patrick Reed and Rickie Fowler.
Out first after an hour's delay to the start because of overnight rain, the pair took control with a birdie at the first hole in the alternate-shot format and were never behind.
The pair had little time for lunch and were quickly back out in the afternoon fourballs against Bubba Watson and J.B. Holmes.
The morning could have been even better for the Americans had Watson not lost his normally red-hot touch with the putter against Adam Scott and Marc Leishman.
First the 2012 and 2014 Masters champion missed a seven-footer for par at the 16th to enable the Internationals to level.
Then he missed an even shorter one to win the match on the final hole.
Local hero Bae Sang-Moon was involved in final green drama for the second day in a row.
On Friday he had holed a 12-footer to win his match as wild celebrations erupted.
On Saturday, he put his partner Hideki Matsuyama stone dead with his third shot to the par-five to secure a half against Bill Haas and Matt Kuchar.
"I was thrilled for both of us," said a grateful Matsuyama. "We were one down and somehow we pulled it off."
Results on Saturday from the Presidents Cup at the Jack Nicklaus Golf
Club, Incheon, South Korea (par 72). International team first:
Match score: International team 6.5 United States team 7.5
International team 2 United States team 2
Branden Grace/Louis Oosthuizen beat Patrick Reed/Rickie Fowler 3 and 2
Adam Scott/Marc Leishman halved with Bubba Watson/J.B. Holmes
Bae Sang-Moon/Hideki Matsuyama halved with Bill Haas/Matt Kuchar
Jason Day/Charl Schwartzel lost to Dustin Johnson/Jordan Spieth by 1 hole
International: Steven Bowditch, Thongchai Jaidee, Anirban Lahiri, Danny Lee
US: Zach Johnson, Phil Mickelson, Chris Kirk, Jimmy Walker