Challenger Marty Haynes picked off interim District 3 County Commissioner Mitch McClure in Tuesday's Republican primary.
Unofficial Election Commission vote tallies show Haynes took home 56.8 percent of the vote and McClure landed 42.8 percent.
All vote totals, which include federally mandated provisional ballots, are unofficial until certified by the Tennessee Division of Elections.
"We worked hard. We felt good going into the race at the start," Haynes said Tuesday night. "It's just a culmination of broad-based efforts."
Of three county elections on Tuesday's ballot, only two had contested primaries -- the Republican matchups in special elections for District 3 and county mayor.
This year's special elections are being held to fill vacancies created in the positions in January 2011 when former County Mayor Claude Ramsey became deputy governor of Tennessee and then-District 3 Commissioner Jim Coppinger was named interim county mayor. Winners of the Aug. 2 general election contests for those posts will serve until 2014.
With 100 percent of precincts reporting, Coppinger received 87 percent of the countywide vote, beating out challengers Basil Marceaux I and William Turner.
Coppinger will face Democrat Richard "Rick" Wilson and independent Richard Ford in the general election.
A regularly scheduled property assessor primary contest had two unopposed candidates.
Both Democrat Jelena Butler and Republican Bill Bennett will face independent Conrad Taylor for property assessor in August. The winner of that election will serve until 2016.
In District 3, Haynes will face Democrat Mitzi Leigh Yates on Aug. 2. McClure will continue to serve as commissioner until Sept. 1.
"I'm going to keep serving my community," McClure said. "I knew it was going to be close. Ultimately, it's either God's will or it's not. I'm a highly spiritual person in that regard."
Haynes said his campaign will take off a couple of weeks before reaching out again to voters.
"I'll have to reach out to those folks who supported Mitch in this race," he said.