Former Charleston county councilor Curtis Bostic's second-place finish in Tuesday's 1st district Republican primary election in South Carolina was upheld by a Friday recount, confirming his advancement to a runoff against former governor Mark Sanford.

Bostic narrowly finished ahead of state Sen. Larry Grooms on Tuesday, triggering an automatic recount, even as Grooms had bowed out of the race. The recount did virtually nothing to alter the margin between the two. In the end, Bostic outpaced Grooms by 494 votes.

Bostic, an underdog in the campaign, will face Sanford in an April 2 runoff election. The former governor, who fell from grace dramatically in 2009 after disappearing from the state and admitting to an extramarital affair, finished at the top of the 16-candidate GOP field on Tuesday, but failed to win a majority of the vote. That's why a runoff will decide the nomination.

The 1st district special election was triggered when Gov. Nikki Haley (R) appointed Republican Tim Scott -- the former representative of the 1st district -- to the Senate to replace Republican Jim DeMint, who resigned his seat earlier this year.

The winner of the Sanford-Bostic runoff will face Democrat Elizabeth Colbert Busch in the May 7 special general election. Colbert Busch is the sister of Comedy Central host Stephen Colbert.

The 1st district leans heavily Republican; Mitt Romney won nearly six in 10 votes there in 2012.