Washington (CNN) Matt Bevin, the tea party favorite who lost bitterly to Mitch McConnell in 2014, claimed victory Tuesday over his opponent, James Comer, who refused to concede in the expensive and nasty fight for the Republican nomination for governor of Kentucky.

Only 83 votes separated Bevin and Comer with all precincts reporting, according to unofficial results from The Associated Press. Comer called for a recanvass of the vote late Tuesday evening, but pledged to support Bevin if the results held.

"We've gone through a lot together in this race, and you never stopped fighting until the last vote was counted," Comer said. "Whoever is the winning when this re-canvass is finished, I can make you one promise: We're going to elect a Republican governor in November."

A surprise candidate who was once considered a political hanger-on, Bevin managed to last in a race defined by outside groups with ties to the Koch brothers and the donor network organized by conservative powerbroker Karl Rove. Super PACs and political nonprofits went to war in the Bluegrass State, firing off negative ads and fueling personal attacks.

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