Rory McIlroy and Sergio Garcia lost on the final green as the United States edged into a 2½-1½ lead after the first session on the opening day of the Ryder Cup.
The European pair fell to Phil Mickelson and Keegan Bradley after a riveting fourball match which saw them one up with three to play.
Justin Rose and Henrik Stenson beat Bubba Watson and Webb Simpson 5&4, while Jordan Spieth and Patrick Reed defeated Ian Poulter and Stephen Gallacher by the same score.
Thomas Bjorn and Martin Kaymer shared a half with Rickie Fowler and Jimmy Walker on a sunny, breezy morning at Gleneagles in Scotland.
|Friday's fourballs (Europe first)|
|Justin Rose & Henrik Stenson won 5&4 v Bubba Watson & Webb Simpson|
|Thomas Bjorn & Martin Kaymer A/S Rickie Fowler & Jimmy Walker|
|Stephen Gallacher & Ian Poulter lost 5&4 to Jordan Spieth & Patrick Reed|
|Sergio Garcia & Rory McIlroy lost 1down v Keegan Bradley & Phil Mickelson|
Europe have not led after the opening session since the K Club in 2006.
"This whole early morning was pretty much an ebb from the US standpoint, and then we got some flow going," said United States captain Tom Watson.
"Fortunately we're a couple of paces ahead at the moment but it's a marathon."
World number one McIlroy and Garcia, playing his seventh Ryder Cup, pitted Europe's star pairing against a formidable American duo who were undefeated in three matches together at Medinah two years ago.
The encounter took on added significance after veteran Mickelson's "litigation" jibe earlier in the week, although McIlroy downplayed it as a bit of fun.
Spain's Garcia drew the first real roar of the morning when he conjured a spectacular holed bunker shot on the short fourth to give Europe the lead.
Bradley's par four was the best anyone could do at the seventh and Mickelson added a birdie at the par-five ninth to put the US in front.
|Friday's foursomes (Europe first)|
|Jamie Donaldson & Lee Westwood v Jim Furyk & Matt Kuchar|
|Justin Rose & Henrik Stenson v Hunter Mahan & Zach Johnson|
|Rory McIlroy & Sergio Garcia v Jimmy Walker & Rickie Fowler|
|Victor Dubuisson & Graeme McDowell v Phil Mickelson & Keegan Bradley|
On the next, Bradley holed his birdie putt from the fringe to spark his first real fist pump reminiscent of his excitable Medinah celebrations, and when McIlroy missed from six feet the Americans were two up.
But the Europeans stemmed the rising US tide with wins in par at the 11th and 13th to get back to all square. Bradley saw his short putt run around the rim and stay out for the win on the 14th and Mickelson also missed a chance for a half on 15 as McIlroy's par took the Europeans one up.
Bradley's second big fist-pumping moment came when his eagle putt dropped for the win on the 16th and a half in pars took them up 18, which Mickelson, playing in a US record 10th Ryder Cup, won with a birdie four after the Europeans' costly tangle with the greenside bunker.
"We didn't have our best stuff, it was tough conditions," said Mickelson.
"The eagle that Keegan made on 16 was huge because it gave us huge momentum coming down the stretch."
Rose and Stenson teed off first at 07:35 BST in front of huge, boisterous crowds, and edged in front with a birdie from the Swede at the second.
|BBC golf correspondent Iain Carter:|
|"Keegan Bradley and Phil Mickelson's win was huge for the Americans because, not only does it give them the point advantage, but also it reinforces the legend of Bradley and Mickelson.|
|"The Americans' other strong partnership - Bubba Watson and Webb Simpson - was blown away so captain Tom Watson needed them to pull through."|
They extended the advantage with a Rose birdie at the short fourth, and another Stenson birdie on the long ninth beside the water put Europe three up.
England's former US Open champion Rose made it four with a two at the downhill par-three 10th and sealed the first point for Europe with a birdie on the 14th.
Poulter has been Europe's top-scorer in the last three Ryder Cups with a win ratio of 80% but he and Scottish debutant Gallacher came up against a pair of rising US stars in Spieth and Reed.
The American rookies won the first and surged clear with five birdies, in six holes from the sixth, with both playing their part.
Gallacher won the 12th with a par to stop the rot but two more halves in par were all the Americans needed to sink Europe's Medinah hero.
"It was very quiet around our group and that was what we had to do today," said Spieth.
"I don't know if we were originally going to go out together when we arrived this week but we managed to convince the captain and it means a lot that he has that trust in us."
In the second match on the course, the Europeans raced to a three-hole lead after four before Fowler grabbed the first US birdie at the fifth and 35-year-old rookie Walker's stunning eagle three from the bunker at the ninth won another hole back.
Denmark's Bjorn won the 13th with a birdie but Walker kept his side in it with a birdie via a chip-in at the long 16th and holed a birdie putt on the 18th to secure the half.
"There's a sense of disappointment when you're two up with two to play but it was a pretty even match and we have to take it on the chin," said Bjorn. "We played good early on and not so good in the middle."
|Ryder Cup 2014 on the BBC|
|Friday, 26 September: BBC Radio 5 live, 08:30-19:00. The Ryder Cup Highlights: 20:30-22:00, BBC Two; 20:30-22:00 BBC Two Scotland; 23:05-00:35 BBC Two Wales; & 20:30-22:00, BBC Two NI.|
|Saturday, 27 September: BBC Radio 5 live, 08:30-18:30. The Ryder Cup Highlights: 20:30-22:30, BBC Two.|
|Sunday, 28 September: BBC Radio 5 live, 11:00-18:30. The Ryder Cup Highlights: 19:30-21:30, BBC Two.|
|Live text & radio commentary, and video highlights, of all three days available on the BBC Sport website.|