As soon as you call her "country," Williams will break into a swanky blues walk. When you think you have her pinned down as a folkie, she'll lead her band into a rock tune. Williams herself realizes just how tricky she is to define. At one point at her Friday concert on the University of Utah campus, she introduced "Get Right with God" as the song that won her a "Best Female Rock Vocal" Grammy, before adding, "It's anything but a rock song."

Friday's show, though, was a rockier affair than typical for Williams. Several times she stepped back from her microphone to dance to the raucous sounds coming from her three-piece backing band, led by excellent guitarist Doug Pettibone. Songs like "Atonement," "Unsuffer Me" and "Come On" all had an added kick missing on their recorded versions.

Given that Williams took the stage in a Led Zeppelin t-shirt, jeans and knee-high boots, her focus on rock material shouldn't have been a huge shock. But her version of concert standard "Joy," complete with riffs lifted from Led Zeppelin and The Doors courtesy of Pettibone and opening act Kelly Joe Phelps' dueling guitars was a surprise.

"Rescue" from Williams' "West" album opened the show with a sparse arrangement, but Williams quickly built some momentum with stellar takes on "Fruits of My Labor," "Words" and "Those Three Days," which featured some excellent vocal harmonies from Pettibone.

Not every song was a home run; "Sweet Side" had Williams straining to hit some notes, and her efforts at spoken-word/rapping on songs like "Righteously" don't really work, despite their strong lyrics.

Williams is better when evoking the R&B and soul music she grew up on. "Still I Long for Your Kiss" was the best performance of the night, while "Essence" and "Greenville" were both highlights as well.

By the time Williams and her band had delivered 16 songs over the course of 90 minutes, she was loose and dancing almost non-stop, chatting up the crowd between each song. For a mercurial performer like Williams, a show full of smiles is all her fans can ask for.

Who: Lucinda Williams When: Friday Where: Kingsbury Hall, Salt Lake City The Bottom Line: The genre-defying Grammy winner leaned heavily on her rock and roll side in a memorable show.