March Madness has taken hold in Kentucky's U.S. Senate race.

Two of the top four contenders in the May 18 primaries are graduates of Duke University and their opponents are hoping to parlay the Big Blue Nation's disgust for Blue Devils into votes.

On Selection Sunday, Republican Secretary of State Trey Grayson began running ads on KentuckySports.com, the Lexington Herald-Leader's University of Kentucky sports news site, and other sports sites that tell viewers to "Beat Duke, Vote Grayson."

"In March, there's one big difference between Rand Paul and Trey Grayson," says the ad, which then shows an unflattering picture of Paul with a caption that says "I'm Rand Paul and I'm a Duke Blue Devil."

Paul's campaign responded Sunday night by saying Grayson's campaign has become a joke.

"Well, I guess that might be a real issue if you're running for student council," Paul said in a statement. "It's especially funny watching my Harvard-educated opponent complain about where I went to medical school."

Grayson graduated from Harvard in 1994 before graduating from UK's College of Law in 1998. Grayson campaign manager Nate Hodson said the ad is a light-hearted spot meant to energize supporters.

"We're having some fun as we work to organize our campaign through the volunteer and bumper sticker sign ups we will receive," Hodson said. "Plus, it let's us show some pride in the Commonwealth during an exciting time of year."

Those who click on the ad are taken to Grayson's campaign web site, where they can request a bumper sticker or watch a short video that shows Paul introducing himself to a crowd as a "Duke Blue Devil." Grayson then says he's proud to be a UK Wildcat.

In the Democratic primary, Lt. Gov. Daniel Mongiardo offered in a news release on Monday to bet Attorney General Jack Conway that UK would advance farther in the NCAA tournament that Duke.

"If Jack loses, Jack will serve as my golf instructor at Louisville's Audubon Country Club, where he is a member," said Mongiardo, who graduated from UK Medical School. "If I lose, I will serve as Jack's hunting guide on a wild turkey hunt in Western Kentucky."

Read more of this story at Kentucky.com