The Punch Brothers with Chris Thile performing live in Savannah earlier this year.

Flickr user Jennifer Leigh.

For such a seemingly nice group of young gentlemen, The Punch Brothers sure can be a maddening lot.

It’s not that they weren’t perfectly enjoyable performing Wednesday at the Power Center. In fact, the quintet played a mesmerizing 90-minute show that was full of pleasant surprises.

It’s just that it’s nearly impossible to pigeonhole exactly what they do.

Which is probably no accident, as leader and mandolin virtuoso Chris Thile clearly thrives on eclecticism.

The Punch Brothers look like a bluegrass band, but they play as much like a jazz combo or a string quintet as anything else. So much for easy classification.

For our purposes, we’ll call it “chamber bluegrass” — and to say the Punch Brothers do it better than anyone else would be inaccurate, since no one else does what they do.

On Wednesday, Thile led the group through its paces, transitioning seamlessly from mountain breakdowns to haunting chamber pieces, and from stacked harmonies to avant-jazz discordance. They even threw in a cover of the Beatles’ “Martha My Dear,” just to further defy categorization.

And that was just in the first half of the show, before they really became esoteric.

Following a short break, the group — which includes Thile, banjoist Noam Pikelny, bassist Paul Kowert, guitarist Chris Eldridge and Gabe Witcher on violin — returned to perform its showpiece, “The Blind Leaving the Blind,” Thile’s 40-minute, four-part suite that vaguely chronicles the breakup of his marriage a few years ago.

The Punch Brothers perform “The Blind Leaving the Blind 1st Movement, Pt. 2”:

Even the saddest country song can’t touch this piece for pathos. It’s just that Thile, a veteran of the Grammy-winning, million-selling Nickel Creek, masks the piece’s heartbreak in an compelling detachment that never really defines its narrative.

On Wednesday, the band members told the story with their instruments, providing a musical storyline that was never flashy, yet left no doubt about the players’ individual mastery of their instruments, nor their ability to play together as fluidly as the finest bebop veterans.

The dapper and charming Thile — sort of a pickin’ and grinnin’ Justin Timberlake — was the focal point. Unmistakably the premier mandolinist of his generation, and one of its all-time greats, he redefines the instrument with a subtle touch, only occasionally taking off on the remarkable pyrotechnics that defined his time in Nickel Creek.

The rest of the band showed the same restraint, serving the tunes rather than their own egos, creating a musical tapestry at once compelling, challenging, engaging and, more than anything, enjoyable. No small feat, but one they pulled off without seeming to break a sweat.

Will Stewart is a free-lance writer for AnnArbor.com.