Grace and Oosthuizen were undefeated together in five Presidents Cup matches before the emerging star pairing of Fowler and Thomas schooled them 3 & 2 on in four-ball on Friday.
The Internationals entered Saturday morning's foursomes session six points down and squarely on life support, and under clear skies and cooler temperatures, the US pulled the plug on this 12th Presidents Cup, winning 3.5 of four points in the morning and pushing its lead to 11.5-2.5.
Nick Price is retaining hope the International Team can produce an unlikely comeback after another "tough day" at the Presidents Cup.
Having fallen two points behind after Thursday's play, the global team would have been confident of chopping down the gap a little in the fourballs on Friday.
The perfectly judged effort from the 24-year-old was met by rapturous applause from the watching galleries and Thomas was keen to raise the noise levels even further following his timely birdie. Live coverage continues on Saturday behind the red button from 1.00pm and uninterrupted from 5.00pm.
The United States surged into an 8-2 lead after Friday's four-ball matches at the Liberty National Golf Club. "It was just one of those - keep it in play. fight, fight 'til the end". The Americans won 13 holes on the back nine.
Jason Day and Marc Leishman paired up for a third time match this week and suffered their second consecutive loss, going down 4-and-3 to world No.2 Jordan Spieth and Patrick Reed. A par by the Amercians was good enough to win the 14th, and a final 8-foot birdie putt by Reed on the 15th closed out the match.
With both foursomes and four-ball action scheduled for Saturday, the United States need to collect 7.5 points from a possible eight to decide the competition. To get a half out of it was probably disappointing, but also pleasing.
However, the first point of the day for the Americans came courtesy of Cup rookies Charley Hoffman and Kevin Chappell, who responded to Stricker's call up by combining brilliantly to dispose of Anirban Lahiri and Charl Schwartzel 6&5.
SHOT OF THE DAY: Thomas holed out from a bunker on No. 14 and wound up halving the hole when it looked as though the lead would be cut to 1 up.
In amongst that he virtually left Schwartzel one-out against the Americans with a string of bad shots.
Oosthuizen will team with Day against Spieth and Reed in the first afternoon match.
The South Africans were unbeaten as a partnership in the 2015 Presidents Cup, where Grace went on to take his singles match to go 5-0-0 for the week, and extended their winning run against their Floridian opponents.