Por Jeff Clemetson | Editor

There was a moment during the Aug. 6 Metallica concert at Petco Park where singer James Hetfield explained to the new, uninitiated fans of the band that “Metallica is heavy.”

It was a perfect, if unneeded, description of the group’s sound, which has gone through a lot in its 36-year career — an early lineup shakeup at lead guitar; the tragic death of original bassist Cliff Burton; a public meltdown following the departure of Burton’s replacement Jason Newsted that was captured in the documentary “Some Kind of Monster”; and a public relations disaster when drummer Lars Ulrich waged a war against fans who illegally downloaded music off the internet.

Through all of that, Metallica remains the most successful band in history to give fans “heavy” music — especially when they do it live like they did at Petco.

The show kicked off with a one-two punch of the band’s first and second tracks off its latest album, “Hardwired … to Self-Destruct.” Up-tempo thrasher “Hardwired” and the crunchy, head-banging anthemic “Atlas, Rise!” mark a return to Metallica’s early speed metal sound and fans new and old reacted positively to the new material — proving that after over three decades, Metallica can still both stay relevant and appease its most diehard followers.

Next the band brought it way back with “For Whom the Bell Tolls,” followed by “Creeping Death” from 1984’s “Ride the Lightning” album, which showed just how well the new material fits with the band’s earliest work.

The “Black Album” ballad “The Unforgiven” followed, giving Hetfield a chance to show that his vocal capabilities stretch beyond the gritty growl he is famous for.

“Now That We’re Dead” — another song off the new album — featured a mid-song drum break with Hetfield, lead guitarist Kirk Hammett and bassist Robert Trujillo joining Ulrich’s solo on large, tribal drums that were rolled out on stage. Sticking with new material, the band then launched into a blazing “Moth Into Flame” — a song about the perils of drug addiction — while the mega-screens backing the stage flashed scenes of a video depicting back alley drug culture.

The sitar-like sound of the intro to “Wherever I May Roam” brought a roar from the crowd as Metallica launched into the “Black Album” anthem about touring life.

“Halo on Fire,” one of the more subdued (for Metallica) songs off the new album, was followed by a funky jam with just bass and guitar. The jam segued into Hammett’s solo which featured bits of “I Disappear” — a song Metallica recorded for the “Mission: Impossible 2” soundtrack. Trujillo then took a solo of his own that included a nod to his predecessor, playing part of Burton’s bass solo “(Anesthesia) – Pulling Teeth.”

“Whiplash,” the first single off the band’s debut album, “Kill ‘Em All,” followed the solos and was appropriately greeted with a large mosh pit as Hetfield sang: “Adrenaline starts to flow; you’re thrashing all around; acting like a maniac … Whiplash!”

“Black Album” staple “Sad But True” came next, followed by “One” — the only complete song played from 1988’s “…And Justice For All.” With its multiple movements, “One” was a musical highlight of the night, showing Metallica’s prowess at handling complicated, progressive song arrangements that depart from the usual verse/chorus.

Another song from the band’s progressive era, the title track to “Master of Puppets” followed and featured some finger-smoking guitar solos by Hammett. The anthem “Fade to Black” followed and fan-favorite “Seek and Destroy” closed out the set.

Returning to the stage for the encore, Metallica launched into another “Ride the Lightning” track — “Fight Fire with Fire.” They closed out their encore with two more from the “Black Album” — “Nothing Else Matters” and their biggest radio hit, “Enter Sandman,” which included a brief outro of “Frayed Ends of Sanity,” again from “…And Justice For All.”

Heavy is what people go to Metallica concerts for and heavy is what they got — in large metal doses.

—Jeff Clemetson can be reached at [email protected].