From the experimental days of recording My Aim is True on off-days at the cosmetics factory, to his current, stately position as UCLA’s 2001 artist-in-residence, Elvis Costello is a portrait of musical diversity. The very definition of the term “Renaissance Man,” Costello has remained true to his word: that his legacy promises to leave only the most inspired music in its wake and the evolving certitude to pursue whatever turns him on the most has so far proved realistic.

Never without a challenge, the bespectacled post-punk icon has taken a novel turn as jazz crooner. By setting rearranged Charles Mingus jazz compositions to his own quirky and heartbreaking words, this not-so-unique approach to lyricism has been done before (read: Joni Mitchell’s 1979 record, Mingus), but who knew Costello could sound so damn good and pull it off so well?

The eleven-piece Orchestra eased into the proceedings with a double shot of cool. Alex Foster, bandleader and woodwind whiz, led the charges into the special-dark chocolate vibe of “Midnight Sun.” Sweet, yet darkly biting, it ended with an elegant splash. “New Night” produced a beefy, bassoon undertone and broke through to an undulating midsection.

Arriving to a thunderous applause, Costello, the long-time Mingus champion (he even recorded a tribute track way back when), briefly explained his adoration of the composer, right down to the film-noir song titles; he seemed to pigeonhole feelings with each one. “This Subdues My Passion” was a spot-on rearrangement that found the leather-clad songster keeping time in true jazz style, loking as cool as he should have. On “Jelly Roll,” Costello’s verbal picture clearly reflected the song’s intended emotionthat of black minstrels painting their faces just to get work in the roaring 20s. The super-swanky slide trombone gave this one a sexy, New Orleans glisten of sweat.

Much like his first appearance of the night, it was the Latin calliope sounds of Costello’s own “Floodland” that got the loudest reaction. With tongue approaching cheek, he explained how the words to the next sublime selection ensued; hunkered over a piano, slurping on a martini glassfull of milk, “Invisible Lady’ came to him in a not-so drunken state. As the profound bassoon signaled its introduction, the tune soon moved into an epoch Copa Cabana swing that had Costello striding smoothly in the spotlight.

The second set opened with Sy Johnson, responsible for all of the songs’ rearrangements, taking a turn as conductor through the haunting and murky “The Chill Death.” One of Mingus’ earliest pieces, it was written in the 1940s when the maestro bassist was just 17. As the story goes, Mingus felt that he could meditate himself so soundly, that he could die and not even know it. Heavy stuff for teenager, but then again, Charles was a heavy cat.

The mood was lightened by “Don’t Be Afraid, The Clown’s Afraid, Too.” More than just a circus song, this be-boppin’ swinger was easily the most fun opus of the night. It had our hero screaming primal into the microphone that helped thwart the song perfectly. “Weird Nightmare,” would drag the audience back into wicked iniquity, but Costello’s hit “Watching the Detectives” was there just in the nick of time.

As the encore rolled around, though, it illustrated that while this is one of the more unique concerts to hit the Big Apple in a lot of years, the tone of the second half did little to keep the mood rising. The up-and-down nature seemed to set the tone for a modicum of disappointment. Then again, maybe Costello wanted us all to salivate and long for more. The weepy “Almost Blue” found wagging tongues wanting a more upbeat score to end the night. Despite the patriotic lyrics of “Hour of Sleep” tugging on heartstrings, and Costello’s emotive pleading to the audience, it would have been better served in the middle of set I and replaced with a monster Costello original. It should be noted again that Elvis’s voice was near perfect all night and was idyllic for what he was looking to accomplish. His emotive gestures proved he’s fully immersed in the Rat-Pack role.

There are no other future concert dates set, so this rare treat is something the audience can look forward to bragging about. And as for the future of Elvis Costello and the Charles Mingus Orchestra, the album has already been recorded (as guests of another tribute, the Mingus Big Band). This is clearly an experiment Costello will tinker with for the next year or so as he completes his residency on the left coast.