Sen. Mark Warner of Virginia addresses an election night rally on Nov. 4 in Arlington. (Brendan Smialowski/AFP/Getty Images)

Sen. Mark R. Warner’s campaign knew his reelection bid would be a nail-biter, a top adviser said Tuesday, but tried to hide that fact to keep national Republicans from rallying to challenger Ed Gillespie.

“We knew it was closer than most people knew,” adviser David Hallock recalled. “This race wasn’t going to be decided at 9 o’clock.” Shortly before the election, he said, he changed his phone’s ringtone to Guns N’ Roses’s “Welcome to the Jungle.”

In fact, Gillespie did not concede until Friday in a race that was decided by fewer than 18,000 votes. Six years ago, Warner won his seat with a 32-point margin.

Gillespie’s campaign, in contrast, saw enthusiasm everywhere, spokesman Paul Logan said: “We could definitely feel a wave building.”

But the team did not have the numbers to back it up. The campaign’s last poll, taken three weeks before Election Day, showed the former Republican National Committee chairman down by double digits. With several more-certain competitive races across the country, the big donors stayed out — just as Warner had hoped.

A blue Virginia tide turns red for 2014

Hallock and Logan spoke freely and at length to an audience at George Mason University in Arlington County.

“The Warner campaign was largely successful,” Hallock said, in projecting an “aura of inevitability” that kept outside Republican groups from investing in Gillespie.

“We didn’t want to acknowledge that . . . the race was getting closer, even though we knew it, for fear of bringing outside forces and money and creating enthusiasm on our opponent’s side,” he explained. But that success “created kind of a Catch-22 for us” that made it hard to inspire turnout among Democrats, Hallock said. Motivating Democrats to vote was the campaign’s biggest challenge. In Democratic strongholds, Warner consistently garnered less support in last week’s election than Gov. Terry McAuliffe (D) did in his victory last year.

“In our polling and our traveling around the state, the real lack of energy and enthusiasm across the board really was palpable,” said Hallock, who has worked for Warner since 2010. “They were kind of beating their heads against the wall a lot of times trying to get folks to volunteer, trying to get folks to engage.”

As Warner himself did last week, Hallock attributed that “malaise” to a frustration with Washington inaction as well as activist fatigue after the 2012 and 2013 campaigns — not with the senator’s “reflexively bipartisan” style.

The campaign spent about $3 million, said Hallock, on a field operation — part of a 2-to-1 advantage over Gillespie.

“More money would have been the key,” Logan said.

With such a profound disadvantage in money and name recognition, he added, the Gillespie campaign focused heavily on using their candidate strategically and relying on volunteers. Every ad included Gillespie speaking to the camera “to make people comfortable with Ed.”

Gillespie, who is also a past state party chairman, held conference calls with supporters to explain his strategy and take questions.

“We were targeting very hard those independents and soft Republicans who we saw as the lowest hanging fruit for us,” said Logan. The campaign used robo-calls coordinated with congressional candidates to target those voters.

Hallock credited Gillespie with running a “very disciplined” campaign that effectively cut into Warner’s support among Republicans and independents.

“The ‘97 percent,’ which was part of just about every ad that the Gillespie team ran, was an effective, very simple, very direct message,” said Hallock, referring to Warner’s record of voting with President Obama 97 percent of the time. Warner’s campaign tried to counter that narrative by emphasizing that the president weighs in on only a fraction of votes, of which many are routine nominations. But, Hallock added, the attack was effective at “peeling away part of the historical coalition that we put together.”

Logan said the most damaging attack from the Warner campaign was a focus on Gillespie’s past lobbying work for Enron.

Asked about one of the race’s buzziest ads — Gillespie’s spot declaring his opposition to “the anti-Redskins bill” in Congress — Logan said the idea stemmed from a joint forum at the Loudoun Chamber of Commerce.

Warner did not say whether he would support a Democratic bill that would revoke the National Football League’s tax-exempt status if the organization continues to back the Redskins name. Gillespie did.

“We saw that was potentially an issue,” Logan said. So they recorded 15 seconds of Gillespie talking to the camera and spent $50,000 to run the ad on cable during a Monday Night Football broadcast of a Redskins game against the Dallas Cowboys.

“It certainly made a splash,” Logan remarked — and it played into Gillespie’s message that Congress was focused on the wrong things.

“That $50,000 probably could have been spent better elsewhere, in my opinion,” said Hallock. “It created a little buzz for about 24 hours, but I’m not sure it moved votes.”

He said the Warner campaign started using “addressable television” — a relatively new strategy of reaching specific voters’ television sets.

“We’re just kind of on the first edges of it,” he said, adding that about 150,000 Virginians have a television that can be directly targeted.

The cross-party discussion of election strategy was hosted by the Virginia Public Access Project and moderated by Mark Rozell, acting dean and professor of public policy at George Mason’s School of Policy, Government and International Affairs.