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Deadheads in 2015 spend a lot of time holding their breath. The long, strange trip (allegedly) ended in July, when the Core Four — surviving original members Bob Weir, Phil Lesh, Bill Kreutzmann, and Mickey Hart — played a string of farewell shows at Chicago’s Soldier Field, resurrecting the Grateful Dead moniker for the first time since Jerry Garcia’s 1995 death. Joined by Phish’s Trey Anastasio, who covered Garcia’s guitar parts, and longtime collaborators Jeff Chimenti and Bruce Hornsby, the gigs went off without a hitch: career-spanning setlists, engaging noodle-fests, and, by all accounts, a rekindling of the atmosphere that made Dead shows of yesteryear the stuff of legends.

But the appearances often felt perfunctory. The Dead’s three Soldier Field shows, as well as their two Bay Area warmup gigs –made available to fans outside of Chicago and California through pricey livestreams – epitomized the trepidation fans old and new had about the performances: From exorbitant hotel packages to numerous secondary viewing options, the experience felt startlingly commercial for a band that always predicated its existence on bootlegs and hippie-era communalism.

So, when news broke that three of the Core Four — sans Lesh, their influential bassist — would hit the road again under the name Dead & Company with John Mayer in tow just months after cashing in on “the end,” the skepticism rolled in. The 38-year-old guitarist’s comments about the project didn’t help. “I think Pandora was to thank,” Mayer told Billboard in August. “I actually came in from being outside in the pool, I was dripping wet and had to see what was on the iPod. … I feel like my generation has SiriusXM to thank. The Grateful Dead station on Sirius is its own experience, especially if you drive. If you live in Los Angeles, it’s such a brilliant way to score the commute.”

Weir, always second fiddle to Garcia but equally crucial to the band’s sound, had looked disengaged at the July shows and caught flak from Deadheads for curtailing Anastasio’s attempts at sonic exploration. (Weir cheekily acknowledged this in the encore of the final Chicago concert when he wore a “Let Trey Sing” shirt onstage.) Bringing an almost exuberantly naive Deadhead on tour and spurning Lesh — who played merely 30 miles away in Port Chester, New York, as Dead & Company rocked a Halloween crowd at Madison Square Garden — seemed like a recipe for disaster.

But Mayer’s naiveté also signaled a possible blessing. Despite attending one of this summer’s farewell shows, he’s too young to have a connection to the original Grateful Dead in a live context. Instead he’s cited the 36-volume live recordings series Dick’s Picks — the go-to source for novice Deadheads without bootleg know-how — as his entry point into the band’s live oeuvre. “I kind of represent this new generation of future Dead fans,” Mayer told Billboard, and Dead & Company’s appearance at the Garden seemed poised to live or die with the musician Rolling Stone once hailed as one of “the new guitar gods.”

And skepticism be damned: This Mayer-fronted iteration of the iconic jam band surpassed expectations in just about every way. Freed by his philosophy as a modern Dead acolyte, Mayer enthusiastically guided the group through a murderer’s row of its best songs, achieving a degree of six-string magnetism that eluded prior Garcia devotees who stuck to his script too rigidly.

From the start, Mayer felt surprisingly integrated with Weir, Kreutzmann, and Hart. (Chimenti and current Allman Brothers Band bassist Oteil Burbridge filled out the ensemble.) Weir offered Mayer a musical olive branch on first set opener “Jack Straw” when he traded verses with his peer — like he once did with Garcia — signifying a willingness to hand over the reins that continued through the entire show. In focusing on songs from the Dead’s early ‘70s, country-rock oriented period, Dead & Company’s first set also played to Mayer’s strengths. He brought blues-rock swagger to Altamont-honoring “New Speedway Boogie” and fiery vigor to ’80s Garcia cut “Althea,” and he hopped for much of his solo on the set-closing “Deal.”

The youthful vibe — Mayer is 13 years Anastasio’s junior, and three decades younger than any member of the Core Four — only increased during the band’s second set. Although the group didn’t embark on one of the Dead’s signature half-hour psychedelic excursions like “Dark Star” or “The Other One,” it blazed through four of the middleweights in its catalog: “Truckin’,” “Estimated Prophet,” “Eyes of the World,” and “Terrapin Station.” Mayer silenced naysayers who had doubted he could traverse Garcia’s proggy late ‘70s riffs, but his triumph wasn’t the only one on stage. Burbridge plucked through Lesh’s tricky bass parts with ease, while Chimenti provided the keyboard underpinning that’s essential to the Dead’s style. Kreutzmann and Hart gelled on percussion, and Weir delivered a passionate performance, even strutting the stage during “Prophet.” The extended jams simply felt more vital than the majority of those in July’s Fare Thee Well concerts.

All the components, including Mayer’s soulful vocals, converged for Dead & Company’s final sequence. The band played its famed flower-power pairing of “China Cat Sunflower” and “I Know You Rider” — which has sometimes been uncoupled since Garcia died — before launching into an acid-soaked “Morning Dew” and Weir’s raucous “One More Saturday Night.”

Rather than choosing a traditional encore like “Sugar Magnolia” or “U.S. Blues,” the group busted out “Werewolves of London,” the Warren Zevon cover that the Dead performed at only a handful of its more than 2,000 concerts, including Halloween gigs in 1985, 1990, and 1991. Most of the audience joined Mayer and Weir for the song’s famous howls, moved to shout “Wah-ooooooo!” rather than merely sigh in relief.