McIlroy and McDowell got GB & Ire off to a flier at St-Nom-la-Breteche
Britain and Ireland edged in front against Continental Europe on the first day of the Vivendi Trophy in Paris.
After the opening round of fourballs, GB & Ireland took a slender 3-2 lead at the St-Nom-la-Breteche course.
Graeme McDowell and Rory McIlroy won 4&3, Anthony Wall and Chris Wood 6&5 and Simon Dyson and Oliver Wilson 3&2.
But Europe fought back well with Anders Hansen and Francesco Molinari winning 4&3 and Miguel Angel Jimenez and Gonzalo Fernandez-Castano 2&1.
Paul McGinley's defending champions are without the likes of Paul Casey, Padraig Harrington, Lee Westwood and Ian Poulter, but they got off to a flying start.
English debutants Wood and Wall led the way with an emphatic win over Henrik Stenson and Robert Karlsson, while McIlroy and McDowell were similarly untroubled as they saw off Denmark's Soren Kjeldsen and Spain's Alvaro Quiros.
It's a long time to be at the course at a quarter to nine if you're going to tee off after midday
European captain Thomas Bjorn
The Northern Irishmen both revealed they would love to continue their partnership at next year's Ryder Cup at Celtic Manor.
"I hope it's the start of a long partnership," said McIlroy. "As long as we stay fit there's no reason why we can't have a partnership for the next 10 years."
McDowell added: "Obviously we're great friends, but this is a chance to show we can gel on the course. There's nothing I would like better than to play with him in the Ryder Cup."
Denmark's Hansen and Italian Molinari eventually got the Europeans on to the leaderboard by beating Robert Rock and Steve Webster, before Dyson and Wilson beat Danish number two Soren Hansen and Sweden's Peter Hanson.
The final pairings were crucial and Spaniards Jimenez and Fernandez-Castano managed to fight back from two down and then hold off a late challenge from Ross Fisher and Nick Dougherty to win on the 17th.
European captain Thomas Bjorn said he thought having the opening ceremony on the morning of the first day did little to help his side.
"There's no excuses for not being ready, but being a Scandinavian myself a few of them I know are very set in their routines," said Bjorn.
"I could see a lot of things going on that maybe unsettled them a little bit and they maybe weren't quite ready when they stood on the first tee.
"I might not have gone over it well enough. It's a long time to be at the course at a quarter to nine if you're going to tee off after midday. It's not quite what you want to do, but they should all have the experience."
Bjorn also shrugged off concerns over Karlsson, who was playing competitive golf for the first time since a four-month spell on the sidelines due to a blister behind the retina in his left eye.
"To be fair to Robert, he can obviously play a lot better than he did, but he didn't play all that bad," added the Dane.
There is another round of fourballs on Friday, followed by greensomes (when partners both drive on each hole, but then choose one ball) and foursomes on Saturday and then singles on Sunday.
Britain and Ireland have beaten Continental Europe four times in a row in the biennial tournament, formerly called the Seve Trophy, which works on similar matchplay lines to the Ryder Cup.
Scores from Thursday's fourballs (GB & Ire team first):
McDowell & McIlroy bt Kjeldsen & Quiros 4&3
Wall & Wood bt Stenson & Karlsson 6&5
Dyson & Wilson bt Soren Hansen & Peter Hanson 3&2
Rock & Webster lost to Anders Hansen & Molinari 4&3
Fisher & Doughty lost to Jimenez & Fernandez-Castano 2&1
Friday's fourball pairings (GB & Ire team first):
1035 BST: Dyson & Wilson v Stenson & Quiros
1050 BST: Dougherty & Fisher v Peter Hanson and Soren Hanson
1105 BST: McDowell & McIlroy v Hansen & Molinari
1120 BST: Rock & Webster v Fernandez-Castano & Karlsson
1135 BST: Wall & Wood v Jimenez & Kjeldsen