There are many reasons Saturday night's Faith No More concert could make a fine contender for the least likely show of the summer. For one thing, Philadelphia is one of just four U.S. cities that the Bay Area group has booked since ending a decade-plus hiatus last year. For another, the Mann Center is a pretty ambitious billing for a band that had only a couple of hit singles in the early '90s.

Then there is the fact that the rap-rock progenitors managed to attract so many black T-shirts and inventive body piercings to a venue that typically plays host to top-class orchestras and jazz luminaries.

"We don't usually play this kind of place," front man Mike Patton admitted gratefully.

But that did not make him the least bit sheepish. For opening acts, Patton brought along former Roots member Rahzel for a bawdy set of virtuosic beatboxing and foulmouthed anti-comedian Neil Hamburger. And when Patton and company finally took the stage, they did not deliver the long-awaited salvo of heavy-metal angst but rather a cheeky subversion of Peaches & Herb's old R&B hit "Reunited."

It was a bold move for a band vulnerable to accusations of the typical reunion circuit cash-in, but the audience's blank stares suggested more confusion than amusement.

Faith No More quickly put fears to rest, however, tearing into their hits "Epic" and "Midlife Crisis" and die-hard favorites like "From Out of Nowhere." Patton's Axl Rose yowl remained lithe and limber above his bandmates, who cooked with all the energy and rock-star theatrics of a group half their age.

They were at their best when their mutant-metal eclecticism gave way to more focused explorations: The soulful "Evidence" and piano-pop cover of the Commodores' "Easy" were the night's highlights, and made the pile-driving riffs and Patton's black-metal growl all the more effective when they returned. By the time Faith No More closed its set with the Asiatic reggae of "Just a Man," the entire house was swaying outstretched arms to the rhythm.

When band members reappeared for the encore, keyboardist Roddy Bottum asked if the crowd had missed them. Whether he meant the last five minutes or 12 years, the answer was loud and clear.