Like the shocking defeat of House Majority Leader Eric Cantor last June, neither pundits nor polls saw how much trouble the Virginia incumbent was in. Democratic Sen. Mark Warner appeared to fight off a surprisingly tough re-election challenge, narrowly defeating GOP candidate and former Republican National Committee Chairman Ed Gillespie, 49.1 percent to 48.6 percent, according to preliminary election results. Polls in the late stages of the campaign had shown Warner with an average lead of 10 percentage points over Gillespie.

Warner's margin of victory is small enough that Gillespie can request a recount. The state doesn't have any automatic recount rules, but a recount can be requested if there is a less than 1 percent vote difference.

“All of our modeling has Warner winning this,” said "Meet the Press" moderator Chuck Todd. But "if I were [Gillespie], I wouldn't concede tonight," he said.

Gillespie could ask for a recount within 10 days of the state certifying the election results. A special recount court decides the rules of recount. The court's decision as to the winner of the race is final, according to Hampton Roads ABC affiliate WVEC.

After a nail-biting evening, as the returns came in far closer than expected, Warner hung on thanks to the voters in Fairfax. The state remains split between the Democratic-leaning D.C. suburbs and more conservative voters, but President Obama carried the state twice.

Slightly more than half of Virginia voters said the economy was the most important issue facing the economy, and Warner narrowly won those voters over Gillespie, 49 percent to 48 percent, according to NBC News exit polling. Of the 29 percent of voters who said health care was the most important issue, Warner got 71 percent of the vote to Gillespie’s 26 percent.    

Warner also had a slight advantage with the 58 percent of voters who said they approved of U.S. military action in Iraq and Syria. Warner got 51 percent of those voters to Gillespie’s 48 percent.

The senator also had a 50 percent to 48 percent advantage among the 68 percent of voters who said they were married. Non-married voters --  32 percent of the electorate --  strongly preferred Warner to Gillespie, 58 percent to 37 percent.

Warner outraised Gillespie by nearly $10 million, according to figures from the Center for Responsive Politics. Warner raised $16.3 million to Gillespie’s $6.8 million.