John Curtis, the Provo mayor, won Utah's GOP primary special election Tuesday night. He will face off against Democrat Kathie Allen and third-party candidate Jim Bennett, son of the late GOP Sen. Bob Bennett of Utah, to determine who will fill the House seat vacated by Rep. Jason Chaffetz.

Three Republicans squared off in Utah’s 3rd Congressional District in a bid to replace Chaffetz, the former chairman of the House Oversight Committee who abruptly resigned from Congress in June after slowly climbing through the political ranks for his persistent investigations into Hillary Clinton’s emails.

Former state lawmaker Chris Herrod received the GOP nomination at the party's state convention, while Curtis and Tanner Ainge -- son of Boston Celtics general manager and former Brigham Young University player Danny Ainge -- acquired enough signatures to place their names on the ballot.

Curtis, who was endorsed by Utah’s Republican Gov. Gary Herbert, faced criticism for having once been a Democrat. But he is now considered the favorite to win the U.S. House seat.

Ainge called Curtis to concede and congratulate him on his victory.

"The numbers were too insurmountable," Ainge’s press aide said.

This is one of seven special elections scheduled this year to fill vacant seats in the House and Senate. Alabama held a special election of its own Tuesday, to select party nominees to fill the U.S. Senate seat once held by Attorney General Jeff Sessions.

The Associated Press contributed to this report.