After torrential rain and wind early in the day forced a seven-hour suspension in play, the Americans recovered superbly to open up leads in two of the four opening fourballs against the Europeans.
Europe, bidding to regain the trophy they lost at Valhalla two years ago, led in one match while the other was all square as play was called to a halt at around 20:00 SA time. All four matches will be completed on Saturday.
It represented a dramatic shift in momentum for the Americans, who had trailed in three of the four matches before rain forced organisers to suspend play for the first time since the 1997 event at Valderrama.
A dreadful morning for the Americans was compounded by the embarrassing disclosure that their wet weather gear was leaking. Team officials scrambled to a merchandising stall at the event to buy replacement waterproofs.
US skipper Corey Pavin was delighted by the American fightback.
"It was a tough day, but the fans were great - they stuck around and waited around and I'm delighted we got back out," Pavin said. "I'm pleased and very proud of the guys for how we came back."
Europe counterpart Colin Montgomerie meanwhile said the early session on Saturday could be crucial.
"There's no match that is anymore than two up or two down, so everyone is still in the game," Montgomerie said. "There's a very important session tomorrow morning to gain that momentum back again".
The rain forced organisers to announce a radically altered schedule in a bid to allow for the golfing showpiece to be completed by Sunday night.
Officials said the final two days would now comprise a second session comprising six foursome matches instead of the usual four, meaning all 12 players on each side will be involved.
A third session of play will then comprise two foursomes and four fourballs, followed by the traditional 12 singles matches.
However, officials admitted the tournament was at the mercy of the weather, and with more rain forecast a Monday finish was a possibility.
Both captains welcomed the amended schedule.
"All credit to the organisation for coming up with a plan. It's great for the fans," Montgomerie said. "Monday finishes are no good in any sport."
Pavin also said he wanted to see a Sunday finish.
"I think some very smart people got together and tried to figure the schedule out," he said. "Colin and I agreed it was a very good idea - allow the cup to finish on Sunday weather permitting."
The star of the show for the Americans was Pavin's wildcard pick Stewart Cink, who produced some red hot putting to rattle in five birdies as his partnership with Matt Kuchar finished two-up after 12 holes against Northern Irish duo Rory McIlroy and Graeme McDowell.
World number two Phil Mickelson also inspired a fightback with Dustin Johnson in a gripping game with European stars Lee Westwood and Martin Kaymer in the opening fourball.
Westwood and US PGA champion Kaymer had got off to a flying start to go three-up after six holes.
But Mickelson conjured up a trio of birdies on the ninth, 10th and 11th to reduce the Europeans' lead to one hole with six holes remaining.
The third game was also delicately poised, with England's Ian Poulter, partnering Ross Fisher, rattling in a 25-foot birdie putt to level at all square after 10 holes as darkness fell in their tussle with the heavyweight pairing of Tiger Woods and Steve Stricker.
Montgomerie said Poulter's putt had given Europe precious momentum heading into Saturday.
"Very important," Montgomerie said. "It was dark, very, very dark. A fantastic effort. That will give us momentum we need to carry forward into a very, very busy day tomorrow."
Pavin will also have been pleased by the performance of rookies Bubba Watson and Jeff Overton, who made light of the testing conditions and partisan galleries to breeze into the lead against Luke Donald and Padraig Harrington.
The American pair were one up after eight holes as play ended.
Overnight Ryder Cup scores after the first day of the biennial clash between Europe and holders the United States on Friday:
Fourballs
Lee Westwood (ENG) and Martin Kaymer (GER) one up against Phil Mickelson and Dustin Johnson (USA) after 12 holes
Stewart Cink and Matt Kuchar (USA) two up against Rory McIlroy (NIR) and Graeme McDowell (NIR) after 11 holes
Ian Poulter (ENG) and Ross Fisher (ENG) all square with Steve Stricker and Tiger Woods (USA) after 10 holes
Bubba Watson and Jeff Overton (USA) one up against Luke Donald (ENG) and Padraig Harrington (IRL) after eight holes