As he campaigned with frenzied energy along the Virginia coast on the Sunday before Election Day, with a growing sense that an historic upset was in reach, Ed Gillespie made a curious stop — at a Virginia Beach branch of Buffalo Wild Wings, the sports-bar chain.

The Republican Senate candidate wasn’t there to cheer on the Washington Redskins. He was there, amid the framed jerseys of NFL greats and giant-screen TVs, for the sake of Buffalo Wild Wings itself. His digital adviser had crunched the numbers: Buffalo Wild Wings was the second most common Facebook “like” for conservative-leaning independents within his social network — the same kinds of people whom Gillespie desperately needed to get to the polls.

So Gillespie’s campaign posted a picture of him sitting among fans, gazing up at the football game, for his Facebook page. The campaign then paid $100 to ensure the image rose to the top of the Facebook newsfeeds of more than 25,000 carefully selected Virginians — a big-league bang for only a few bucks.

“It made perfect sense to me,” Gillespie said of the decision to spend precious last-minute time staging a Facebook posting in an exclusive post-election interview.

Just two years ago, Republican candidates, by all accounts, lagged behind Democrats in the use of social media and real-time data to reach undecided voters. For an uber-strategist and veteran of the George W. Bush and Mitt Romney campaigns like Gillespie, the lesson was clear: Get serious about data-driven campaigning.

Now, Gillespie is convinced that his shrewd use of information like the importance of Buffalo Wild Wings helped him come shockingly close to defeating one of the Democrats’ top stars, Sen. Mark Warner. Despite election-eve polls showing him behind Warner by 7 points, Gillespie ended up within 16,700 votes — less than 1 percent — of Warner, and he insists that his underfunded campaign’s digital savvy was a key reason why.

“I’m a believer in it,” he said. “I knew we would be outspent and that the digital element of the campaign is a way to help mitigate being outspent.”

In the end, Gillespie spent $5.9 million overall on his campaign, $500,000 of it — or 47 cents per vote — on digital targeting. Other Republicans in better-funded races went further: Iowa’s Joni Ernst and Colorado’s Cory Gardner each spent that much just in the last couple of weeks of their campaigns. They were following a clarion call from Republican National Committee Chairman Reince Priebus to GOP candidates across the country: Close the digital gap with the Democrats as quickly as possible.

Interviews with more than two dozen GOP leaders and political strategists indicate that the Republican Party now believes that it did so, at least in these midterm elections. Gone, for the moment, are the images of Romney’s vaunted Orca vote-targeting machine crashed on the floor of Boston’s TD Garden, or of left-wing Silicon Valley techies congratulating themselves solely on Democratic victories.

“There’s no doubt we closed the gap,” Gillespie argued of his own near-miss.

Of course, it remains an open question whether the Republicans will stay on pace with the fast-moving Democrats in 2016, when many of the Obama alumni consider joining Team Hillary or other campaigns, national and local, with new innovations to match.

But the story of how the Republicans came to embrace technology is arguably one of the hidden keys to the party’s success in the 2014 midterms. It didn’t create the wave that elevated so many Republicans, but it may well have ensured that candidates like Gillespie were able to make the most of it. One challenge for the GOP’s continued success, many strategists believe, will be whether the party’s underfunded insurgents can learn from races, like Gillespie’s, that used technology in a smart, cost-effective way.

Over the final two months of the campaign, POLITICO got an exclusive behind-the-scenes look at Gillespie’s state-of-the-art digital operation that helped him become this cycle’s most striking almost-winner. From the start it was a fittingly obsessive focus for the operation of a campaign insider: Gillespie had been chairman of the Republican National Committee under Bush and watched the party’s historic tech advantage slip away; now, himself a candidate, he pumped out thousands of social media posts, translated his campaign website into six different languages spoken across the state, targeted voters with hundreds of tailored online ads and mined the national party’s real-time database to find and contact more than 1 million potential supporters through old-fashioned door knocks and phone calls.

It almost worked.

***

As the RNC chairman during Bush’s 2004 campaign, Gillespie saw firsthand what microtargeting could accomplish by sending out different messages to different potential voters.

“At that point, buying time on the Golf Channel was seen as a big thing,” he recalled, as if remembering one of Harry Truman’s whistle stops.

Just 10 years later, campaigns like the one Gillespie just mounted for Senate have a rapidly proliferating array of sophisticated new methods for connecting with voters, from streaming video ads on Hulu and YouTube to reaching people on their smart phones, mobile apps and tablets. Add in Facebook, Twitter and other social media, and candidates now have the ability to bypass reporters and speak directly to voters.

For Gillespie, technology was primed to be a great equalizer as he entered the Senate race in January, with Warner having already banked $7 million. Polls from the get-go put the Republican down more than 20 points against his Democratic rival, a popular former governor. He was also running in a state where TV advertising can be inefficient at best — there are eight different markets, crossing borders like North Carolina, West Virginia and Tennessee, as well as the pricey Washington, D.C., market, where two-thirds of viewers aren’t even in Virginia.

“It’s asymmetrical warfare,” Gillespie said. “When you know you’re going to be outspent, you’ve got to spend your money more efficiently, more targeted, and social media enables you to do that.”