John Kennedy has won the Louisiana senate seat held by David Vitter.
The seat is considered safely Republican in the deep red southern state, and Republicans have already secured their majority in the Senate next year.
President-Elect Donald Trump held a rally Friday in the Baton Rouge, asking his supporters to back Kennedy in the election, calling him "a tax cutter" and "true fighter."
"This is an amazing state and tomorrow we need you to go to the polls and send John Kennedy to the united states senate and that's why I'm down here," he said. "He's a great guy."
"We need John in Washington not only for the vote, we need for leadership and everything else but if you go there we'll win," Trump added. "Kennedy is a proven leader who's balanced -- which is amazing -- 16 budgets, returned millions of dollars to taxpayers."
Kennedy defeated Foster Campbell, a public service commissioner with 61 percent of the vote on Saturday.
View the results for the Dec. 10 runoff election here.