Last night's Zero 7 show at the Fillmore in San Francisco was best summed up in a single and decidedly nonmusical moment involving the downtempo outfit's two vocalists, Sia Furler and Jose Gonzalez, as they stood far from center stage.

As Zero 7 principals Henry Binns and Sam Hardaker led their band through a lengthy instrumental jam late in the set, Furler bounced manically all over the back of the stage, returning to the corner to swill her cocktail, perform some off-kilter dance moves, and deliver fake karate chops to Gonzalez, who was playing a shaker and smiling politely at his giddy cohort.

Furler's glee was a pleasure to watch at times, but it was also indicative of the fact that--at least in a live setting--Zero 7 has a tendency to get pretty darn sloppy. Last night's show was a stark departure from the immaculately produced, electro-for the-latte-set sound of the duo's three studio albums.

In addition to Furler and Gonzalez, Binns and Hardaker brought a full band on tour with them. The live instruments added a rich texture to what is already a fairly lush sound. But they also proved to be the show's downfall, bringing a messiness that was ear-splitting at times. Simply put, if the band isn't tight, extended rhythmic jams are the sonic equivalent of a runaway train: It's not going to end well.

Furler, a terribly gifted vocalist, delivered a fine performance on several tracks, including "Destiny" and "The Pageant of the Bizarre." She was often the victim of her own zeal, however, constantly asking for--and getting--more volume in her mic as that volume level reached deafening levels.

But last night's 90-minute set was saved on several fronts by Gonzalez, whose vocals on four songs on the duo's latest album, The Garden, are spectacular. The word on Gonzalez--think Christopher Cross-meets-Jose Feliciano--has been out for a while, with his debut album Veneer drawing rave reviews.

But he particularly shines on stage, and last night was no different, both in his solo opening set and during his Zero 7 songs. A fantastic acoustic guitar player and a wonderfully emotive singer, Gonzalez can be mesmerizing despite playing very quiet music.

That's surely what drew Binns and Hardaker to seek him out last year, and the result--Gonzalez crooning and picking over lush, downtempo beats--provided several highlights last night, particularly the Zero 7 version of Gonzalez's "Crosses." That song, with its buffed-up percussion and building rhythm, commanded the attention of an otherwise preoccupied crowd last night for a lengthy stretch.

That is, until the wheels started coming off at the end.