SANTA CRUZ - It's no crazy notion to think classical music is mostly dead as a relevant art form.

And the notion that contemporary music of the classical kind is its offspring is no crazy notion, either. It's in the latter world that the Cabrillo Festival of Contemporary Music lives.

The formula at this Santa Cruz-based presenter is a simple one: Offer an open musical door into the unknown and give no promises as to what is to be found on the other side.

For an audience, walking through that door is a risky bet. When the music fails to deliver, it can make you pine for Mozart.

But when it delivers, there is nothing more exciting, as was the case during the festival-opening concert Friday evening at the Santa Cruz Civic Auditorium.

The most potent example of how such music can stir an audience to super-emotional proportions happened during Osvaldo Golijov's four movement work "Azul."

If there was ever a piece that spoke to the here and now, this was it. Listening to this work gives a glimpse of what it could have been like sitting in a room and hearing Beethoven roll out a new work for the first time. The excitement was palpable.

"Azul" is a cello concerto conceived as a meditative dialogue for the instrument, written with Yo-YoMa in mind. The inspiration was the Tanglewood Music Festival, the summer home of the Boston Symphony Orchestra in the Berkshires of western Massachusetts. It was there that the lawn and evening sky made a big impact on Golijov.

But although written for Ma, the piece owes a lot to cellist Alisa Weilerstein. This Boston-based cellist worked closely with Golijov to shape the concerto. On Friday, Weilerstein proved that such intimate knowledge of the work really pays off. Weilerstein is one of the most emotive and expressive cellists, and she owns a round and captivating sound. In this performance, she put body and soul into the full service of the music, whose influences ranged from Bach to Piazzolla.

Individuality is secondary in "Azul." The approach is for a holistic piece of music in which the cello is well defined but never is a virtuoso showpiece for the instrument. This approach is what gives the piece so much power.

In the opening "Paz Sulfurica," the melody is born and returns frequently when the cello takes flight and wanders back down to earth in the movement that follows, "Silencio." In the third movement, percussion and accordion play big roles in what turns out to be a thrilling dialogue between percussion and cello. Accordion player Michael Ward-Bergeman, and percussionists Jamey Haddad and Cyro Baptista proved an exotic and integral part of this work. In it there were influences of tango and Sephardic music. And Weilerstein demonstrated that she was not above riffing with these three outstanding musicians.

Some may say this kind of music is nothing more than injecting world music into the classical realm. But with this work, that's an irrelevant point because of the cohesive sound, and how it deeply captivated the audience.

Crucial to pulling this off is conductor Marin Alsop's facility for making contemporary works come alive. This, coupled with the excellent arrangement of musicians she has in the Cabrillo Festival Orchestra made for a winning combination.

This is the kind of contemporary classical music that feels like it has a shelf life beyond the concert hall. The tasty blend of baroque and Latin American influences comes off as so relevant and full of color that the desire to rush out of the concert hall to buy a recording is strong.

This piece proved a contrast to the darkly evocative "Amphitheatre" by Australian composer Brett Dean. This one-movement work penetrated in subtle and shadowy ways. The work was inspired by children's author Michael Ende's book "Momo." It was meant to evoke an ancient amphitheater, and as conceived by Dean conjures dark passages filled with forbidding corners and a sense of evil.

The program also included the world premiere of David Heath's "Rise from the Dark," a neoclassical one-movement work in which emotional melodic lines are juxtaposed against a fraught series of chords. The work did not make a big impression and flirted with redundancy.

The festival continues Saturday with the U.S. premiere of Joby Talbot's "Desolation Wilderness" for trumpet and orchestra. This work is meant to showcase the trumpet virtuosity of Craig Morris. Also on that program are James MacMillan's "The Sacrifice: Three Interludes" and Magnus Lindberg's "Behold the Sun."

On Sunday, the festival concludes with music at Mission San Juan Bautista. The program for that concert includes Ingram Marshall's "Kingdom Come," Kevin Puts' "Two Mountain Scenes," and Aaron Jay Kernis' "Invisible Mosaic III," both West Coast premieres.

Call Bee arts critic Edward Ortiz, (916) 321-1071.