Pat Metheny has spent most of his life on tour, averaging between 120 and 240 shows a year since 1974.

It was 1974 when the celebrated jazz guitarist burst onto the international jazz scene, on a path that would both revolutionize the art of electric jazz guitar and the very instrument itself.

Metheny is still at it, evidenced by his second wine country appearance last Tuesday night. He first brought a special quartet to the Robert Mondavi Summer Festival in the summer of 1988.

For his most recent appearance, he had the good fortune to hook up with a younger musician of like talents, pianist Brad Mehldau, and the keyboardist’s exceptional rhythm section — making up a new quartet for the ages, if you will.

Listening in recent weeks to two new recordings featuring Metheny and Mehldau was enough to make us salivate over the prospect of a live performance.

After taking in that performance last week, I can say without reservation that it will go down as the most important, most creative live concert in Napa Valley in 2007. Yeah, I know — we’ve still got three-fourths of the year to go. Nevertheless, I stand by my assessment.

Metheny and Mehldau are two of the few creative geniuses in jazz today. And there is a mutual respect that is not only evident on stage but has been put into writing in the liner notes for the new CDs.

The guitarist first heard Mehldau play on a Joshua Redman recording on the radio. “When the piano solo started, the playing was so compelling that I had to pull over to the side of the road to listen,” Metheny stated. “It was incredibly strong and original, and exuded a confidence and point of view that I had been hungering to hear from a new player.

“I have followed Brad’s career closely as he has emerged as the major young jazz musician of his generation. His trio has established a way of playing together that is very special and Brad himself has evolved a playing style that encompasses a universe of his own design where he is somehow able to reconcile the larger jazz tradition with a playing language that is informed by the major aspects of the piano’s evolution within the world of Western classical music while making up-to-date reports on the current state of the world all at the same time.”

Mehldau points out that Metheny “is one of the musicians who made me want to play jazz from an early age.

“The first time I heard Pat’s music, I was 13 and a friend of mine gave me some headphones and put on the live version of “Are You Going With Me” from “Travels.” It was one of maybe five or six life-changing moments for me as a listening musician. It hit me so hard emotionally on every level and broke open my whole perception about what was possible in music.

“I put Pat up there with Miles Davis, John Coltrane or Keith Jarrett — musicians who raised the stakes in terms of the expressive possibility and emotional fulfillment a listener can receive from jazz, as instrumentalists, improvisers, bandleaders and composers.”

Metheny’s versatility is almost nearly without peer on any instrument. His body of work includes compositions for solo guitar, small ensembles, electric and acoustic instruments, large orchestras and ballet pieces, with settings ranging from modern jazz to rock to classical.

He’s also a pioneer in the realm of electronic music, and was one of the first jazz musicians to take the synthesizer seriously. Years before the invention of MIDI technology, Metheny was using the Synclavier as a composing tool. He also been instrumental in the development of several new kinds of guitars such as the soprano acoustic guitar, the 42-string Pikasso guitar, Ibanez’s PM-100 jazz guitar, and a variety of other custom instruments.

One of those innovative guitars was featured in Tuesday night’s groundbreaking concert — the double-fretted Celtic-sounding Pikasso that produced, at times, koto-like sounds on a gorgeous impressionistic work by Metheny for guitar and piano, “Sound of Water.”

Playing not only electric guitars but also Synclavier and guitar synthesizer, Metheny revisited past glories and toyed with the future — with the help of Mehldau and his simpatico musical henchmen, bassist Larry Grenadier and drummer Jeff Ballard.

Metheny has always been regarded as an intelligent musician who respects his audiences enough to bring them along on a musical journey that encompasses every aspect of the jazz idiom. With Mehldau, Metheny has met his match.

Their performance at the Opera House ran the gamut of spontaneous combustion to calculated composition breeding familiarity. If I’m not mistaken, the rousing encore contained more than a sample of the classic “House of the Rising Sun.”

A mixture of works for duo and quartet from the two recordings Metheny and Mehldau laid down in December 2005, Tuesday night’s concert featured brilliant musicians with wildly imaginative minds creating new music right on the spot. Sort of improvisation taken to the highest level.

While Mehldau was certainly able to display his huge chops, he also emerged as a remarkably supportive and creative accompanist, freeing Metheny’s guitar and guitar-synth to take flight in various ways, from light and airy to dramatic and, occasionally, frenetic. These guys really understand texture and pacing, allowing a composition to build up its own head of steam and then follow it through to a logical conclusion.

To see these two remarkable talents at work on the same stage was sheer magic — magic shared by a cheering sold-out house.

It was a real coup for Napa Valley Opera House executive director Evy Warshawski and crew to book this incredible pairing for a wine country performance — considering that the tour (which is slated to head to Europe and Japan this summer) had only three dates in Northern California.

If not previously, local audiences (at least the one at last Tuesday night’s landmark performance) now realize the importance of having a venue that can accommodate the amazing talents that pass our way.