GOP businessman Vance McAllister won a special election in Louisiana’s 5th District Saturday night, stunning the heir apparent in the contest to become the next member of Congress.

McAllister, a self-funding newcomer, defeated Republican state Sen. Neil Riser 58 percent to 42 percent, with 78 percent of precincts reporting, according to the Associated Press.

Riser had long been considered a shoo-in to win the special election to replace Rep. Rodney Alexander,

the special election to replace Rep. Rodney Alexander, who resigned over the summer to take a post in Gov. Bobby Jindal’s administration.

.In the Oct. 16 open primary, Riser captured 32 percent of the vote to McAllister’s 18 percent, making him the favorite going into Saturday’s race.

Riser also raised more and spent more than McAllister did, and he had the backing of House GOP leadership, including House Majority Leader Eric Cantor and many House Republicans from Louisiana.

However McAllister’s self-described “outsider” status, as well as some help from the

from the popular reality show family featured on “Duck Dynasty,” helped him pull out a win in the race.

Abby Livingston contributed to this report.