Attorney Mike Lee defeated businessman Tim Bridgewater in the Utah Republican Senate primary Tuesday.
The vote closed the final chapter in the race to succeed three-term Sen. Bob Bennett (R-Utah), who was unable to compete after finishing third at his party's state convention in May.
The returns had the two Republicans running close together for much of the evening until Lee started to pull away. With 1,802 of 2,136 precincts reporting, Lee had 52 percent of the vote to Bridgewater's 48 percent.
Lee's almost 5,000 vote lead made him the winner, according to the Associated Press, which called the race for him.
Given Utah's red-state status, Lee is expected to prevail in November against Democrat Sam Granato, who did not face a primary.
A pre-primary poll released over the weekend showed him trailing by nine points, but had 25 percent of the 581 likely GOP primary voters surveyed as still undecided. The Deseret News/KSL-TV survey, conducted June 12-17, found that 42 percent planned to support Bridgewater and 33 percent were going for Lee.
Bridgewater's campaign launched an aggressive Election Day push. He appeared at several honk-and-waves around the state Tuesday and his campaign planned to make 50,000 calls to its supporters, said Tiffany Gunnerson, a spokeswoman for his campaign, before the vote.
Meanwhile, the Tea Party Express (TPE) launched a get-out-the-vote effort on behalf of Lee on Monday.
The group, which helped Sharron Angle win the Republican Senate nomination in Nevada, planned to get its 375,000-strong national membership to call in to Utah to encourage Republicans to get to the polls for Lee on Tuesday.
"Our membership is excited about Mike Lee's candidacy, and we're working hard to get his supporters to the polls," Bryan Shroyer, the group’s political director, said in a statement.
The group had also spent "tens of thousands of additional dollars" on radio ads supporting Lee.
Both candidates were boosted by endorsements. Lee got the backing of Rep. Ron Paul (R-Texas), Sen. Jim DeMint (R-S.C.) and former Majority Leader Dick Armey (R-Texas) in addition to the TPE endorsement. Bridgewater was endorsed by Bennett, Utah Tea Party organizer David Kirkham, the Chamber of Commerce, former Gov. Mike Leavitt (R) and fourth-place GOP convention finisher Cherilyn Eagar (R).
The National Republican Senatorial Committee was neutral in the primary.