Sen. Lamar AlexanderAndrew (Lamar) Lamar AlexanderWeek ahead: Lawmakers near deal on children's health funding Ryan suggests room for bipartisanship on ObamaCare Time to end fiscal year foolishness MORE’s (R-Tenn.) primary challenger, state Rep. Joe Carr, has picked up the endorsement of conservative talk-radio host Laura Ingraham.

“I’m all in for Joe Carr," Ingraham said on her show on Monday. "I think he's, look, he's no-nonsense, a citizen legislator, he'll be, and he'll be someone who will actually listen to the people.”

“Politicians at some point do have to listen to the concerns of the people, not just the concerns of one or two big, fat interest groups like either LaRaza or the Chamber of Commerce. The people still count, don't they Lamar?"

Her comments came during a segment questioning what Alexander has accomplished during his time in the Senate.

Ingraham's endorsement is the latest signal Carr’s challenge may be picking up some steam, coming less than a week after the Tea Party Patriots endorsed him.

And it gave Carr another opportunity to draw a comparison between himself and Dave Brat, the underdog candidate who orchestrated the shocking primary defeat of House Majority Leader Eric Cantor (R-Va.) earlier this year. 

"After seeing the significant impact Laura had on the Dave Brat-Eric Cantor race, we believe this can be a game-changing moment in this campaign,” Carr said in a statement.

Carr has referred to himself as “the next Dave Brat” and called Brat’s win a “combustible moment” in his primary, one that’s shifted the terrain of the race in his favor.

As with Brat’s race, the issue of immigration reform has taken center stage in the Tennessee Senate Republican primary, with Carr accusing Alexander of voting for “amnesty” in supporting the bipartisan Senate immigration reform proposal last year and touting his own work leading the fight for some of the nation’s most restrictive immigration laws in the Tennessee state legislature.

Still, every poll of the race has shown Alexander with a strong double-digit lead, and he’s picked up the endorsements of a number of conservative stars himself, including former Speaker Newt Gingrich and former Arkansas Gov. Mike Huckabee (R). 

Carr and his supporters, however, believe he could see a late-breaking surge in the final weeks before the Aug. 7 primary.