The win was secured before three pairings had even finished their matches when Thomas Levet conceded Bradley Dredge's par at the 17th hole to give GB&I a 15-10 lead.
Only 14 1/2 points are needed to win, and captain Colin Montgomerie's team ended with a 16 1/2 - 11 1/2 victory.
'I'm delighted, especially coming back the way we did,' said Montgomerie, whose team trailed 4-1 after the first day of four-ball on Thursday. 'To win the singles 7-3 was a real team effort.'
Montgomerie lost his match to Continental Europe captain Jose Maria Olazabal, 2 and 1, in the first match play meeting between the pair since Olazabal beat the Scotsman in the final of the 1984 British Amateur.
Olazabal was happy with his win, which he clinched with a birdie at the 17th.
'I have to say it felt good,' he admitted.
But the Spaniard probably can't help but think his team squandered a chance for its first Seve Trophy since winning the inaugural event in 2000.
'It's something that doesn't feel good in the system,' said Olazabal, who assumed captain duties from injured countryman and trophy namesake Seve Ballesteros.
'But obviously I have to congratulate the Great Britain & Ireland team. They played better than we did.'
The captains were the third group to finish Sunday. But despite Olazabal's spirited win, the GB&I side only needed three more points to win at that point with seven pairings left on the course.
David Howell had already rolled to a 6 and 5 victory over Thomas Bjorn, while Paul Casey had already beaten Niclas Fasth 4 and 3. Montgomerie's side also scored points from Graeme McDowell's 5 and 4 win over Maarten Lafeber, Stephen Dodd's 2 and 1 victory against Jean-Francois Remesy and Paul McGinley's 1-up win over Miguel Angel Jimenez.
Continental Europe picked up its second singles win -- after the fact -- with Emanuele Canonica's 2 and 1 victory over Padraig Harrington.
The other two matches were halved: Englishman Ian Poulter parred 17 to square his match with Peter Hanson; and the final match of the day between Sweden's Henrik Stenson and Nick Dougherty ended when both players conceded birdies at 18.
Dredge was the only player in the field without a point entering the singles matches on Sunday. His clinching 2 and 1 victory over Levet should go a long way in helping him forget the penalty he incurred for having too many clubs in his bag during the second round of fourball matches on Friday.
The Welshman stepped up his game on Sunday, and Friday's mistake was more of an afterthought than anything else once GB&I wrapped things up.
'I practiced a bit and counted the clubs, things like that,' Dredge joked when asked what he did to improve his play after the first three days. 'You know, the basics.'
Levet had fallen 3-down to Dredge after missing a five-foot par putt at 13, but he won two of the next three holes to pull within 1-down. However, he pulled his tee shot into the left rough at the par-3 17th and didn't make the green until his third shot.
Dredge landed his tee shot within 22 feet, and after lipping out a birdie putt, he was conceded par for the win.
With his team needing just five points to win at the beginning of the day, Howell made a statement for GB&I by dominating Bjorn. He opened with an eagle at the par-5 first, made the turn at 2-up and moved 5-up with winning birdies at 10 and 12 and a winning par at 11.
The match was all but over at that point, but for good measure Howell rolled in a 4-foot putt at the 13th to clinch the 6 and 5 victory and give the GB&I team a 10 1/2 - 8 1/2 lead.
Casey took control of his match with Fasth by moving 4-up with a winning par at the 11th and a 3-foot birdie putt at the 12th. McDowell clinched his victory over Lafeber with a 12-foot birdie putt at the 14th.
Hanson and Poulter halved their match moments later to make the score 13-10, and Dodd and Remesy were the next to finish when Dodd rolled in a 15-foot birdie putt at 17 for the win.
Remesy needed to make a tricky right-to-left putt to halve the hole, but he missed, leaving GB&I within just one-half point of winning.