COSTA MESA — With a steady flow of customers and invigorating music by a quartet featuring guitarist Phil Upchurch, Mucho Gusto, a new Costa Mesa nitery, got off to a dandy start Thursday.

The opening (it had been twice delayed) of the club--which proclaims itself a "Jazz Bar & Latin Grill" in pink neon script over the doorway--drew more than 300 people over the course of the evening, according to operations manager George Gallardo, formerly associated with El Matador in Huntington Beach.

"We're doing a lot better than I thought; I expected only about a hundred people," Gallardo said between sets as he stood in his new kitchen. Behind him, his crew was hurrying to serve selections from a limited menu of items such as shrimp and steak \o7 fajitas \f7 and Tex-Mex halibut. (Gallardo said he plans to have a full menu by Tuesday.)

The crowd, which did most of its coming and going between 7 and 11 p.m., split itself between the main room--a light and airy rectangular space with turquoise and sand-colored Southwestern decor--and the slightly smaller bar area.

Those who wanted to focus on Upchurch and his cohorts--bassist Luther Hughes, who is Mucho Gusto's entertainment director, keyboardist Mark Massey and drummer Dave Hooper--sat at one of the 20 or so tables in the main room. As it held forth from a small bandstand toward the rear, the band could be seen clearly seen (there are no visual obstructions) and heard (sometimes too well) as it offered contemporary jazz tunes from Kenny Burrell's snappy blues "Chitlins con Carne" to the laid-back and funky "Night Breeze."

Upchurch--who in his 30-year-plus career has worked with such top names as Cannonball Adderly, Quincy Jones and the Crusaders --was a solid choice to get Mucho Gusto off the ground. Whether he was playing the Roger Miller hit "King of the Road" or Charlie Parker's be-bop opus "Scrapple From the Apple," he found ways to make a scintillating statement.

During "Scrapple," Upchurch--who gets a sweet, singing sound from his hollow-bodied jazz-style instrument--dashed off chordal leaps and played fast, whirling lines before ending with a chorus of strummed chord melody, definitely his strongest suit. The chunky blocks of sound seemed to dance through space; one can easily see why Upchurch earned his fame as a rhythm guitarist.