Belgium's first player to appear in the match had an incredible eight birdies and an eagle in the final fourball game of the day in Chicago.
Partner Lee Westwood, winning his eighth cap, did not contribute a single birdie or eagle to the cause, but together they were able to celebrate a win that kept America's lead down to 5-3 going into the weekend.
Tiger Woods and Steve Stricker were the pair beaten and so, on the Medinah course where he has played two major championships and won them both, Woods lost his first two games just like he did in 1999, 2002 and 2004.
Woods was all over the show in the morning as Justin Rose and Ian Poulter won 2&1.
It was so bad Davis Love had reason to drop him instantly, but that would be a first and the American captain decided to give him another chance with Stricker.
Woods then played far better and was close to producing a three-birdie finish that would have snatched a half, but he was no match for the inspired Colsaerts, making a bid to become the most famous Belgian in history.
"It was a lot of fun," Colsaerts said. "I've never had so much fun and I want to have more.
"There are no tools you can use out there. You've just got go with what you have in your pants."
The most dramatic moment came on the short 17th when, with Woods three feet away, he rolled in a 22-footer for a matching two.
"Tiger played great this afternoon [Friday], but Colsaerts played unbelievable golf," Love said. "Tiger would have beaten anybody else."
What the 29-year-old wild card did was badly needed on a day when Phil Mickelson celebrated becoming America's most capped Ryder Cup player with two wins.
Mickelson, in his ninth successive match, teamed up with pumped-up debutant Keegan Bradley to beat previously unbeaten foursomes duo Luke Donald and Sergio Garcia 4&3, then world number one Rory McIlroy and Graeme McDowell 2&1.
The left-hander clinched that with a glorious iron on the short 17th. "That baby was all over the flagstick, but until you see it land you just never know," he said.
Bradley added: "That shot showed why Phil Mickelson is a Hall of Famer - and I've got so much energy I wish I could go 36 (holes) more."
It had been Davis Love's two current major champions who had given their side the momentum after the morning foursomes had been tied 2-2.
Masters winner Bubba Watson, whipping up the crowd even before he hit a shot, and US Open winner Webb Simpson went to the turn in 29 and were a brilliant 10 under par in winning 5&4 over Scot Paul Lawrie and Swede Peter Hanson, like them omitted from the opening session.
That took the United States 4-2 up and Dustin Johnson and Matt Kuchar made it 5-2 with a 3&2 victory over Rose and Martin Kaymer.
Earlier in the day McIlroy and McDowell hit back from a lengthy rules debate to win on the last green against Jim Furyk and last weekend's £7million 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 Donald - playing in the city that has been his home for the last 15 years - and 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&3 to Mickelson and Bradley, while Westwood and Francesco Molinari were beaten 3&2 by Zach Johnson and Jason Dufner.
The absence of Poulter from the afternoon was the big call by Olazabal. He brings more electricity to the match than anybody and had taken his record to nine wins against only three defeats.
Two of those losses came versus Woods, so to grab his scalp was always going to be huge and his key putt on the 16th was greeted by his now trademark "Come On" roar - and a long, cold star from Woods.
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.
The early dispute was over whether McDowell could take relief from a sprinkler head by the second green.
It would have meant McDowell putting rather than chipping, but with Furyk stepping in and believing it should not be given a second opinion for called for.
"We've been friends a long time," Furyk said at one point to McDowell, but the American also then called for calm when a few boos rang out.
McDowell was eventually told to chip, lost the hole, but he and McIlroy then had six birdies in seven holes, the first of them the result of a genius chip by the 23-year-old from over the fourth green.
Furyk had incurred a penalty on the long 10th when his ball move as he prepared to chip, but he and his partner fought back to level, only for Snedeker to hit a simply 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.
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."