Louisville Businessman Matt Bevin (R) on Monday downplayed the impact of Kentucky Republican Sen. Rand Paul's support for his opponent, Senate Minority Leader Mitch McConnell (R-Ky.)

U.S. Senate candidate Matt Bevin (R). (Mike Lawrence/The Gleaner via AP)

"Rand made this decision before I was in the race. That's his opinion. Rand is one vote. Rand will vote one time," Bevin told reporters at a gathering in Washington at the headquarters of Freedomworks, a tea party group backing his candidacy.

Bevin praised Paul, saying he thinks "highly" of the senator. But he added that he feels Paul's natural base of support is in his corner.

"All the people who ultimately coalesce behind him are already behind me," Bevin said.

Paul told conservative radio host Glenn Beck last week that he endorsed McConnell because "he asked me when there was nobody else in the race." Paul initially tried to chance the subject when Beck asked him about it.

Bevin is a substantial underdog against McConnell ahead of the May 20 primary. McConnell has a large lead in the polls and has outraised Bevin by a considerable margin.

But Bevin argued that he is more electable. The winner of the GOP primary is likely to face Secretary of State Alison Lundergan Grimes (D) in the general election. A recent automated poll showed Grimes leading both Bevin and McConnell by similarly slim margins.

"We run the risk of losing this seat because of a sense of apathy and the sense of fatigue for the career politician that is my opponent in this primary, Mitch McConnell," Bevin said.

McConnell spokeswoman Allison Moore responded: "Matt Bevin is reaching pathetic lows in misrepresenting himself to appear credible. Polling actually shows that self identified liberals are only group more willing to elect Matt Bevin over Mitch McConnell."

Bevin identified the federal health-care law as the issue voters care about most right now.

"When something hits people in their pockets, it wakens them," he said.