POP MUSIC REVIEW : A Hot N’Awlins Night With Dr. John : Music: His spicy mix dug deep into the city’s roots and had the crowd roaring for more.

Everything was in place for Monday night’s concert at the Belly Up Tavern featuring New Orleans legend Mac Rebennack--better known to the music world as Dr. John. The place was filled to capacity; Lagniappe, a local catering company, was dishing up spicy Cajun and Creole food; even the weather cooperated by replicating the steaminess of the Big Easy.

At well after 10 p.m., Rebennack and his current band ambled onto the stage and put a match to this combustible setting with a two-hour show that lived up to the title of Rebennack’s new album, “Goin’ Back to New Orleans.”

Seated at the piano and backed by guitar, percussion, drums, bass and three long-in-the-tooth horn players, Rebennack opened with “Snake Eyes,” an Afro-Cuban-influenced percolator that seemed to motorize every limb in the house. By following with the kinky kineticism of “Wild Honey” and “I Been Hoodood,” Rebennack served notice that the evening’s course was set for the kind of maximum funk that is a throwback to his best efforts.

In the mid-’60s, Rebennack graduated from the New Orleans recording-studio milieu, moved to Los Angeles, fused N’Awlins-style R & B with nascent West Coast psychedelia and assumed the Mardi Gras-cum-Beatles identity of Dr. John Creux, the Night Tripper. Since then, he’s adopted a number of sartorial guises--from the outlandish, “gris-gris” (voodoo) garments, face-paint and feathers of his early days to Monday’s urban-dandy outfit of embroidered black jacket and matching beret.

Rebennack’s music has generally corresponded to these stylistic caprices. In recent years, and following the pattern of a number of artists whose careers have traced an elliptical arc from regional hero to pop sensation and back again, Rebennack has seemed almost preoccupied with a nostalgic re-examination of his roots.

The somewhat conservative 1989 opus, “In a Sentimental Mood,” found him just that--covering such standards as “Makin’ Whoopee!” “More Than You Know” and the Duke Ellington title track. On his last swing through town, Rebennack was accompanied by a small jazz combo.

“Goin’ Back to New Orleans” finds Rebennack coming full circle. The album is at once an homage to and an update of the pungent Southeastern delicacies that make up that city’s musical heritage, and Rebennack’s tour draws heavily from it. A funked-up version of the old-as-dirt jazz tune “I’ll Be Glad When You’re Dead (You Rascal You),” the instrumental finger-snapper “Cowan Woman” and the album’s salsa-fied title track easily proved their concert-worthiness by generating the kind of response normally reserved for favorite hits.

To his credit, Rebennack usually avoids wallowing in past glories, but this show was notable for its near-total devotion to an authentic treatment of the more obscure New Orleans roots music.

The new album’s “Milneburg Joys” drew on the slack strut and near-inscrutable, compound rhythms of the “second line” music heard in the city’s traditional funeral processions. “Life, Love and Money” provided a mid-tempo breather with a swaggering, burlesque blues. And a rich, stretched arrangement of Earl King’s herky-jerky “Big Chief”--written in the early ‘60s for legendary New Orleans pianist Professor Longhair--enabled everyone in the band to swing.

Another King tune, “Let the Good Times Roll” (the one covered by Jimi Hendrix, not the same-named Shirley and Lee classic), saw Rebennack switching to lead guitar, which he played commendably if unspectacularly.

This music brings out the best in Rebennack. Perhaps because the sounds remind him of his mostly happy youth in New Orleans’ Third Ward district, they seem to raise his spirits above his usual stage demeanor. Rebennack was generous with his between-song remarks (although his thick, strangulated accent made many of them indecipherable), and took obvious delight in a slightly bawdy recitative in the middle of one tune. His voice--a strained, nasal-sounding rope wiggled loose by a relaxed delivery and rounded by regional dialect--was in vintage form.

Old-style music also challenges and fully utilizes Rebennack’s appreciable piano skills. On the funky “Renegade,” his fingers tossed a savory salad of barrelhouse-boogie, jazz-blues and Gospel-R & B that would make Leon Russell remove his shades.

And, if you paid too strict attention to the humorous lyrics of the slow blues, “(I’ve Got) A Virus Called the Blues,” you missed the rough-sewn tapestry of keyboard styles and piquant harmonies that Rebennack wove throughout the verses.

When the crowd insisted on an encore, Rebennack and band obliged with a torrid interpretation of Leadbelly’s “Good Night, Irene” that blended blues, Dixieland, rock and R & B. In addition to being an appropriate send-off, the performance underscored how his loving excavations of America’s musical past make Rebennack one of the more intriguing musicians of the present.