With no announcement, speech or spotlight, indie-rocker M. Ward bolted onto a darkened stage and launched into an unadorned but enthusiastic set last Saturday night, before a sold-out house at Bimbo's 365 Club.

Ward stayed in the dimmest light possible through his opening number, a complex but rousing solo guitar instrumental, walking to different parts of the stage every time the lighting engineer got a spotlight on him.

He kept the microphones bent low, so that his back was hunched when he sang, and his eyes stayed hidden in the shadow of his baseball cap for most of the show.

In spite of the shyness of his dress and demeanor, and the low-key tone of many of his studio recordings, Ward's performance was galvanizing. The crowd roared with applause at the beginning and end of almost every song.

"I don't think I need to see this guy with a band," said Phlis McGregor, a journalist for Canada's CBC Radio and a fan in the audience. "By himself you see this powerhouse. Even though he wasn't in your face, he was a huge presence."

"I think he's mostly an indie-rock musician. But towards the end of the set, he got really low, and I started hearing Nina Simone come out. Bluesy and really soulful," McGregor said.

Ward's lyrics showed a similar balancing of sensibilities. They were whimsical and delicately sketched in a comparable vein to writing by Elliott Smith or Thom Yorke, but with a down-home, populist assuredness more often seen in Tom Petty's best songs.

"I used to feel like California, with baby's eyes so blue / Now I feel like Carolina: I split myself in two," Ward sang in "Carolina."

The venue also helped evoke the mood of the evening. Standing across the street from Kennedy's Irish Pub and Curry House on Columbus Avenue, Bimbo's 365 Club surrounds its patrons with the grungy elegance for which the North Beach neighborhood is famous. Glittering red and gold drapery, floor-to-ceiling wall mirrors mounted with chandeliers, and paintings of voluptuous naked women surrounded by exotic fish underwater set a wry, ironic mood of ragtime regality.

"I was amazed by his playing on the guitar," said Gerald Shiebe, 29, a bartender at Bimbo's. "I've heard my girlfriend playing some of his albums, but nothing with that kind of energy. I'm definitely a much bigger fan now."

M. Ward played for six years with the San Luis Obispo trio Rodriguez before releasing his first solo album, "Duet For Guitars #2," in 1999. He signed to Merge Records in 2003.

His most recent album, "Post-War," was called one of the best records of the year by the San Francisco Chronicle, Entertainment Weekly and Allmusic.com upon its release last August.

"Tonight was meant to be James Brown's night," Ward said, referring to the scheduled show the late "Godfather of Soul" was to have played at Bimbo's that night.

"James Brown is dead; long live James Brown," he said, and launched into Brown's tune titled, "I Found Someone."

Ward closed the show by bringing an audience member on stage.

"I'm looking for the piano player from San Francisco, who wants to play a song," Ward said. "I will wait patiently for you to come up."

Two young men jumped on stage. One backed down, throwing his hands in the air and admitting, "I suck! You should play!"

The other man talked with Ward a moment and sat at the piano. "Jonathan, everybody!" said Ward, and launched into the final song. Near the end, Ward gave the cue for a piano solo and, with the player's back turned, left the stage.

The piano player went on, playing along with a repeating loop of guitar strumming Ward had recorded on-stage. After a moment the player began singing the chorus himself, to wild laughter and cheers from the audience.

Ward came back a minute or two later to accompany the piano with a harmonica, closed the song, thanked San Francisco and said good night.

He played a second set on Sunday. It was his last scheduled public performance until he goes on tour with Norah Jones this April.