She took down two country superstars early this week, so newcomer Hayden Panettiere was no match for Carrie Underwood and her new single 'Two Black Cadillacs.' Underwood's fans made quick work of 'Telescope,' winning with over 80 percent of the vote yesterday and last night on Taste of Country Nights radio. 

Today the competition is tougher, as Rascal Flatts fans are every bit as loyal and dedicated as fans of the former 'American Idol' star. The trio have released the title track from their new 'Changed' album as a new single. The ballad finds vocalist Gary LeVox opening up like never before.

Listen to clips of both Underwood's and Rascal Flatts' songs and vote for your favorite here. You can vote once every hour online, so come back and vote often to be sure your artist wins. Hear the full versions of the songs tonight after 10PM on Taste of Country Nights. Help your favorite song win by placing additional votes at (888) 678-9995. Call as many times as you like! You can listen to the show online through any of the 41 radio stations that carry it. Voting will end tonight at 10:40PM CT.

Listen to a Sample of Carrie Underwood, 'Two Black Cadillacs'

Listen to a Sample of Rascal Flatts, Changed'

Showdown Rules: The song with the most votes wins, and the winner goes on to face a new challenger in the next Showdown. Vote as much as once per hour online, and as much as you want by calling (888) 678-9995. If a song wins five days in a row, it will be retired into the Taste of Country Showdown Hall of Fame to allow for new songs to compete. Some songs will be considered for a second Showdown if voter turnout is healthy in a losing effort.