The Presidents Cup remains on a knife-edge, the Americans leading the International team 9.5 to 8.5 ahead of today's deciding 12 singles match-ups.
South African Branden Grace delivered two big shots in darkness on Saturday to keep the Internationals within one point - the smallest margin going into the final day in 10 years.
That's what the International team wanted - and needed - after just one victory in 1998 in Australia.
"We need to win," Louis Oosthuizen said. "This is huge for us."
The South African duo are the first International tandem to go 4-0 in team matches. Tiger Woods and Steve Stricker did it in 2009 for the US.
As Saturday's foursomes and fourballs were both shared 2-2, South Korea's Bae Sang-Moon and Japan's Hideki Matsuyama wrote themselves into Cup folklore with a thumping fourball victory.
They belted Americans Jimmy Walker and Chris Kirk 6 and 5 in the most-accomplished display of better-ball golf of the week, during which they birdied an astonishing nine of the first 11 holes.
Only twice before has a match ended after fewer holes in Presidents Cup history, David Frost beating American Kenny Perry 7 and 6 in 1996, and Korean KJ Choi with Australian Adam Scott, 7 and 6 victory over Tiger Woods and Steve Stricker in 2011.
Earlier on Saturday, world number one Jordan Spieth holed two crucial putts on the final two holes to maintain the US team's slender one-point lead after the morning foursomes.
Spieth, with Dustin Johnson, was up against the man he battled for supremacy in majors all season, Australian Jason Day, who was teamed with Charl Schwartzel.
Again, the Texan won, as he had in the US Masters and Open this year, while Day beat Spieth for the PGA Championship.
Spieth and Johnson were down from the fourth hole, three down at the turn and one down with two to play.
But Spieth rolled in a seven-footer for a birdie to square the match and repeated the feat for a winning par at 18.
Spieth and second-ranked Day won't meet in Sunday's singles, but the Australian will still face a 2015 fellow Major champion in Zach Johnson.
The US PGA champion Day and British Open champion Johnson go head to head on Sunday in the marquee 10th match of the 12 singles encounters at the Jack Nicklaus Golf Club Incheon.
It could prove the pivotal game, with the US holding a slender 9.5-8.5 lead after the four rounds of team fourball and foursomes play were completed on Saturday.
Masters and US Open champion Spieth will be out just ahead of them in the ninth match against Aussie Marc Leishman.
New Zealand's Danny Lee is up third against the big hitting Dustin Johnson, who teamed up with Spieth to beat Lee and Leishman in Thursday's foursomes.
Should the singles go right to the wire, then it will be down to South Korea's Bae Sang-Moon in the anchor match against the American captain's son, Bill Haas, in front of a frenzied crowd in Incheon.
Meanwhile, Melbourne has been announced as the host of the 2019 edition of the Presidents Cup.
The biennial tournament returns to American soil in 2017 at Liberty National in New Jersey before moving to Melbourne two years later.
Which golf course in Melbourne will host the 2019 event has yet to be decided.