It's been an uphill climb, but Brad Paisley's "Mud on the Tires" has finally scaled its way to the top of Billboard's country singles chart. With Keith Urban's "You're My Better Half" idling at No. 2 for a second week, Paisley veered into the passing lane to arrive at No. 1 after a 21-week journey on the chart.

Elsewhere on the country singles chart, Rascal Flatts' "Bless the Broken Road" rises one notch to No. 3, as Darryl Worley's "Awful, Beautiful Life" falls from No. 1 to No. 4. Holding steady at fifth and sixth places, respectively, are Gretchen Wilson's "When I Think About Cheatin'" and Blake Shelton's "Some Beach." Climbing one position each are LeAnn Rimes' "Nothin' 'Bout Love Makes Sense" (No. 7) and Alan Jackson's "Monday Morning Church" (No. 8). Josh Gracin ascends two levels to enter the Top 10 at No. 9. Tim McGraw's "Back When" tumbles three spaces to No. 10.

Dierks Bentley has the highest-debuting single of the week. Landing at No. 46, "Lot of Leavin' Left to Do" is the first single from his new album, tentatively titled Modern Day Drifter. Shelton debuts at No. 52 with "Goodbye Time," a song Conway Twitty took to the Top 10 in 1988. Other singles debuting this week include SHeDAISY's "Don't Worry 'Bout a Thing" (No. 56) and Lila McCann's "Go Easy on Me" (No. 57).

With no new additions to Billboard's country albums chart, it's another week of musical chairs -- especially in the Top 10. Shania Twain's Greatest Hits holds to the top slot, but Rascal Flatts' Feels Like Today ascends one rung to No. 2, pushing former tourmate Toby Keith to No. 3 with Greatest Hits 2. At No. 4 through No. 10, respectively, are: George Strait's 50 Number Ones, Wilson's Here for the Party, Big & Rich's Horse of a Different Color, McGraw's Live Like You Were Dying, Kenny Chesney's When the Sun Goes Down, Paisley's Mud on the Tires and Alison Krauss & Union Station's Lonely Runs Both Ways.

Looking ahead to next week, country's favorite beach boy is expected to make a huge splash on the albums chart. On Tuesday (Jan. 25) -- its first day of release -- Kenny Chesney's Be As You Are: Songs From an Old Blue Chair sold more than 100,000 copies. Executives at his record label project that first-week sales could exceed 250,000. In any event, Chesney already appears to have a lock on debuting at No. 1 on the country albums chart. Other new albums debuting next week include LeAnn Rimes' This Woman and newcomer Blaine Larsen's Off to Join the World.

Also next week, Friday Night Lights, the film starring Tim McGraw and Billy Bob Thornton, is expected to debut at No. 1 on Billboard's DVD sales chart. McGraw's publicist reports that more than 3 million copies of the Universal Pictures film were sold during its first week of release on home video.