Davis Love's two current Major Champions and a pumped-up Keegan Bradley had Europe on the back foot as the United States threatened to take a grip on the Ryder Cup in Chicago.
After the morning foursomes had been tied 2-2, Masters Tournament winner Bubba Watson - whipping up the crowd even before he hit a shot - and US Open winner Webb Simpson led a fourball charge.
On a Medinah course set up for low scoring they birdied eight of the first ten holes to be six up on Scot Paul Lawrie and Swede Peter Hanson, like them omitted from the opening session.
Bradley then continued his earlier form to put himself and Phil Mickelson, with nine appearances in the match now America's most capped player in history, four up after eight holes against World Number One Rory McIlroy and Graeme McDowell. He had contributed four of their six birdies.
Behind them Justin Rose and Martin Kaymer trailed by two to Dustin Johnson and Matt Kuchar after six, but Tiger Woods - after a defeat to Rose and Ian Poulter full of wild shots and missed putts - and Steve Stricker were level at the same point against Westwood and Belgian debutant Nicolas Colsaerts.
Earlier in the day McIlroy and McDowell fought off a stunning US comeback to win on the last green against Jim Furyk and last weekend's US$11,000,000 man Brandt Snedeker.
But after Europe had led in all four games two hours into the eagerly-awaited clash, the Northern Irishmen's victory followed the first-ever foursomes defeat for both Luke Donald - playing in the city that has been his home for the last 15 years - and Sergio Garcia.
After six successive wins in the format for Donald and eight wins and a half for Garcia since he made his debut in 1999, they went down 4 and 3 to Mickelson and Bradley.
Westwood and Francesco Molinari were beaten 3 and 2 by Zach Johnson and Jason Dufner, another of American Captain Love's rookies, but then Rose and Poulter won 2 and 1, Poulter producing a key putt on the 16th that was greeted by his now trademark "Come On" roar.
From three down with six to go - Furyk had incurred a penalty on the long tenth when his ball move as he prepared to chip - the Americans fought back to level, only for Snedeker to hit a dreadful drive down the last.
There was still work to be done when McDowell hit into the bunker short of the green, but his partner splashed out to five feet and the 2010 match-winner made no mistake.
McDowell told his American girlfriend Kristin, attending her first match: "Welcome to the Ryder Cup - hope you enjoyed yourself.
"That match to me just personifies it. You're playing against two very gutsy players who clawed their way back.
"But we had stacked our team with this finish in mind. I wanted Rory hitting the tee shots on 16 and 18 and our strategy paid off."
McIlroy added: "Fortunately for us, Brandt didn't hit the best of tee shots on the last."
McDowell may have shown nerves of steel to win the cup back at The Celtic Manor Resort, but they had affected him when he was called on to hit the first tee shot.
It clipped a tree barely 100 yards off the tee, but Furyk also went badly left to emphasise what stage-fright can do to even the most experienced players.
Poulter took his cup record to nine wins in 12 games, but two of the three defeats had come against Woods and he said: "I never wanted wanted to have another one".
Woods hit a spectator on the head for the second day running and he and Stricker were three over par when they lost, easily the worst scoring of the session.
Donald said of the defeat for him and Garcia, who were looking to make it five out of five together: "We played solid. They just played a little better."
Watson and Simpson could not make it a record-breaking margin of victory - that stands at 7 and 6 in fourballs - but 5 and 4 did them nicely and put the Americans ahead in the match.
McIlroy and McDowell were three down with six to go, Rose and Kaymer had the same deficit at the turn, but an inspired Colsaerts took himself and Westwood two up with eight holes remaining.
He holed from 22 feet for his fifth birdie on the ninth, then made a five foot eagle putt at the 578 yard next.
Woods won the 11th with a birdie, but Colsaerts made the gap two again with an 18 footer for a two at the difficult 13th. He had already notched six birdies and an eagle.
McIlroy's birdie won the 14th and Rose's 25 foot putt at the 12th narrowed the European deficit there to two as well.