Unless you had a trace of Nostradamus in your bloodline, there was no earthly way of knowing what to expect last Friday night when two of rock’s most enigmatic geniuses kicked off their oddly compelling tour at Hard Rock Live in Hollywood.

In one corner, we had the groundbreaking artistry and tortured soul of the Beach Boys’ Brian Wilson; in the other, we had Jeff Beck, the man Rolling Stone listed as the No. 5 greatest guitarist of all time—even though casual music aficionados would be hard-pressed to name a single song from the mostly instrumental solo career of the one-time member of the Yardbirds.

What we did know going in was that Wilson recently had invited Beck to record some music with him; the sessions went so well that their collaborations will appear on Wilson’s next album, due in 2014. That, apparently, led to the idea of a month-long U.S. tour. But questions loomed: Would the same audience interested in a true rendering of classic Beach Boys music appreciate an hour’s worth of mesmerizing instrumentals? And when they did share the stage, how would Wilson’s surfin’ safari sounds mesh with Beck’s mastery of the whammy bar?

The answers arrived before an enthusiastic but disappointing turnout that forced Hard Rock to curtain-off the back section of the arena, which only seats 5,500. Those who considered attending but begged off for whatever reason should be kicking themselves. You missed one of the year’s most fascinating evenings of music—not to mention glimpses into the minds of two of rock’s most towering and influential figures.

Wilson took the stage first, joined by a 12-piece ensemble that included original Beach Boys Al Jardine and David Marks. Last year, following a celebrated and abbreviated 50th-anniversary tour with the surviving members of the Beach Boys, it was announced that the Mike Love-version of the band would continue to tour without Wilson, Jardine and Marks. It would take decades to sift through the rifts, rubble and fractured history of the Beach Boys, but Love is never far from the carnage. Wilson was later quoted that “It sort of feels like we’re being fired.”

On Friday, it felt more like he had been liberated. Yes, at 71 and having battled his share of psychological demons, Wilson sometimes can appear a little catatonic behind his white piano. But en masse, the Brian Wilson Band makes Love’s incarnation—which occasionally invites actor John Stamos to play drums—sound like a recently fired Ramada Inn lounge act.

A 19-song set that included Beach Boys classics from “California Girls” to “Good Vibrations” featured brilliant, pitch-perfect harmonizing and lush walls of sound that would have brought Phil Spector to his knees. A three-song run from the masterpiece “Pet Sounds”— “God Only Knows,” “Wouldn't It Be Nice” and “Sloop John B”—managed to replicate and embellish the sounds that emanated from an album credited with influencing The Beatles’ “Sgt. Pepper's.” Before playing “God Only Knows,” Wilson told the audience, “Paul McCartney said this was a pretty song. I hope you so think so too.”

After a short break, Beck emerged in his trademark sleeveless shirt with a five-piece band—including standouts Rhonda Smith on bass, Lizzie Ball on violin and Nicolas Meier holding his own on guitar—that he later said was playing “its first proper gig.” If there was any inaugural-night lack of cohesion, it didn’t show.

The 69-year-old led the crowd on a captivating journey of searing, soulful and, at times, haunting and hypnotic instrumental work worthy of his standing as a guitar god on par with the likes of Jimi Hendrix—with whom Beck jammed on stage in New York City in 1968 during a series of shows with The Jeff Beck Band (can you even imagine what that must have been like)? It was fitting that Beck’s take on the Hendrix classic “Little Wing” proved one of the set highlights, but it wasn’t the only one.

Wilson’s band returned during Beck’s set for four songs, including “Surf’s Up,” which may very well have been the high point of the evening. Any doubts that Beck’s signature guitar couldn’t complement an epic Wilson treatment were put to rest during a song whose title famously suggested, when it was recorded in 1966, that the Beach Boys’ less-complex, surfing music was history. The sound of Beck’s emotive guitar playing over the beautiful harmonies produced music so ethereal that you didn’t want it to end. The same can be said of "A Day in the Life," Beck's show-stopping treatment of The Beatles' famous song off "Sgt. Pepper's."

The show concluded with a three-song encore of Beach Boys numbers followed by Beck’s wrenching rendition of “Danny Boy." Let's face it: This night could’ve have gone any number of the ways. But in the end, the geniuses knew exactly what they were doing.

Brian Wilson Set
Do It Again
Shut Down
Little Deuce Coupe
Then I Kissed Her
Surfer Girl
In My Room
Summertime Blues
California Girls
Heroes and Villains
Old Man River/Cottonfields
That's Why God Made The Radio
Sail On, Sailor (with Blondie Chaplin)
Do You Wanna Dance
Help Me, Rhonda
I Get Around
God Only Knows
Wouldn't It Be Nice
Sloop John B
Good Vibrations

Jeff Beck Set
Eternity’s Breath/Stratus
Even Odds
You Know, You Know
Yemin
Little Wing
You Never Know
Where Were You
Big Block
Our Prayer (with Brian Wilson Band)
Child Is Father of the Man (with Brian Wilson Band)
Surf’s Up (with Brian Wilson Band)
Don’t Talk, Put Your Head on My Shoulder (with Brian Wilson Band)
Brush With the Blues
Rollin’ and Tumblin’
How High the Moon
A Day in the Life

Encores
Barbara Ann
Surfin’ U.S.A.
Fun, Fun, Fun
Danny Boy