You didn’t have to be a rock fanatic to predict the highlight of the Sammy Hagar & David Lee Roth concert last Saturday at the Tweeter Center in Camden, New Jersey, a suburb of Philadelphia. It came halfway through the show, when Diamond Dave sang Van Halen’s greatest hit and only #1 single, "Jump." The spandex-clad frontman had already pranced his way through an hour and a half of VH classics, but he saved his most flamboyant moves for last. Flexible as ever at 46, he did his trademark flying split off the drum riser at the end of the song. His best trick, though, came during the synth solo, when he grabbed a silver baton and launched into a frenetic twirling routine. As he took a bow and chucked the baton aside to start the final chorus, the crowd roared its approval. And however much fans may have missed Eddie Van Halen, that didn’t seem to diminish their joy at seeing Dave pull off his vintage VH moves.

The Sammy & Dave tour, which hits the Tweeter Center in Mansfield this Wednesday, is both a dream-come-true for Van Halen diehards and one of the most bizarre outings in rock history. Ever since Sammy replaced Dave as Van Halen’s frontman in ’85, the two have had nothing nice to say about each other. The rivalry reached its peak in ’96, when Dave replaced Sammy to record two new tracks for the band’s Best of Volume I (Warner Bros.). After that, all hell broke loose: the group ended up rejecting both Sammy and Dave in favor of former Extreme frontman Gary Cherone, only to part ways with Gary after one album. Then they staged another failed reunion with Dave. Most recently, Eddie fought cancer and separated from his wife, actress Valerie Bertinelli, and the band parted ways with Warner Bros. after 25 years. They have yet to find a new frontman.

Which has left a Van Halen void that Sammy and Dave have been only too happy to fill. The tour is also an opportunity for fans to subject the pair to the Van Halen equivalent of the Pepsi Challenge. The hipster party line has always favored Dave, even though Sammy had one of the most successful replacement-singer runs in rock history. Boston all-ages rockers Piebald said it best a few years ago in an open letter to VH called "David Lee Rock": "Well we can’t believe that you replaced him with Gary Cherone/Before that it was Sammy and the hit ‘Poundcake’/Not much better in our books." Sammy hits aside, Van Halen without Dave just never felt right to a large segment of the rock world.

When my stepfather drove me and four of my teenage friends to see Van Halen in Buffalo in the fall of ’91, none of us felt the need to take sides. We loved Dave, sure, but we also loved Sammy and "Poundcake" — as long as Eddie was playing guitar, we didn’t care who was singing. We bought bootleg concert T-shirts in a Burger King parking lot on the way to the show, we screamed our heads off when Eddie played "Eruption," and we swore by VH’s For Unlawful Carnal Knowledge (Warner Bros.) over the other big rock albums that came out that year from Metallica, Guns N’ Roses, and, yes, Nirvana.

But even in my 14-year-old’s state of euphoria, I knew something was wrong. Sammy insisted on performing as little Dave material as possible when he fronted the band, and that night was no exception: "Jump," "Panama," and "You Really Got Me" were the only Dave-era tunes in the set. A few years later, my high-school buddies and I went to see Van Halen in Buffalo again and flipped out when Sammy sang the Dave classic "Unchained." The last time I saw VH was with Gary in Hartford — my home-town crew didn’t make it, but it was the best show I’ve seen the band do. They opened with "Unchained" and mixed seminal Sammy and Dave tunes for the first time in concert. The rock world at large shunned Gary, but hardcore Van Halen fans knew better: as Eddie was fond of saying, he was the best pure singer the band ever had, and when he was on stage, he had nothing but the fans in mind.

Given all the years of bad blood among Dave, Sammy, and Eddie, I was happy to live with that ’98 Gary show as my ultimate Van Halen concert experience. But this summer’s Sammy & Dave tour was something I knew I couldn’t miss. And though the guitarists were a couple of unknowns named Victor Johnson and Brian Young, not Eddie Van Halen, the show didn’t disappoint. Even if Sammy did as many solo tunes as he did Van Halen songs. Even if the most recent tune Dave sang came out in ’86. Even if I had to drive from New York City to Camden to see it.

The biggest problem at the beginning of the tour was figuring out who was going to headline. "Let’s flip for it," Dave suggested, and they agreed to alternate: Dave is headlining the Mansfield show, but it was Sammy’s turn in Camden. So the night began with Dave strolling on stage around 8 p.m. in a pink-and-black checkered suit, inviting the crowd to start enjoying happy hour as the drum intro to "Hot for Teacher" thundered behind him. And he was off, busting karate moves left and right, smiling devilishly, and hitting on chicks in the front row.

Dave may be one of the most notorious symbols of heavy-metal excess, but the most effective part of his show is its simplicity. No pyro, no keyboards, no costume changes — just four guys, a video screen, and 19 of the greatest rock tunes ever written. He sprayed whiskey on the crowd during "Mean Street"; he talked shit about a dude who threw a bottle at him during "So This Is Love?" The baton-twirling routine wasn’t the only trick up his sleeve: he revved his engine on the microphone during the supremely horny "Everybody Wants Some!!" and pulled off some elegant acoustic-guitar fingerpicking as a prelude to the showstopping "Ice Cream Man."

As for the band, well, the most accomplished guy on stage was bassist James LoMenzo, who played with White Lion in their heyday. But they sounded awesome, especially guitarist Brian Young, who was recently plucked from the long-running Hollywood–based Van Halen tribute band the Atomic Punks. He was the only instrumentalist to play a solo all night, and that may have been the biggest difference between this tour and a real VH show, where Eddie, bassist Michael Anthony, and drummer Alex Van Halen get 10 minutes each. It takes a bigger diehard than I am to complain about a missing drum solo, but Young’s spot was short and sweet, featuring clever improvisations on some of Eddie’s most popular themes.

At 54, Sammy is the dean of all Van Halen frontman, and also the one with the most distinguished solo career. Since leaving the band, he’s put together a new group of his own, released three albums, and toured incessantly. His endearing concert shtick includes hiring local strippers to serve him margaritas between songs and letting select fans watch the show on stage from behind the band. Last Saturday, he played way more VH songs than he did on his previous tour (which was recently documented on the Cabo Wabo Birthday Bash Tour home video) and still made plenty of time for his solo hits.

Sammy had Dave beat in the T&A department: along with the scantily clad waitresses, he had cameras hunting for girls in the audience with their shirts up. The party really got started with the string of Van Halen tunes he did in the middle of the set. He mingled with his on-stage peanut gallery during "Why Can’t This Be Love," giving them hugs and passing the microphone around. And like Dave, who referred to his old mates as "the great Van Halen band," he stopped to wax nostalgic about the good old days. He introduced "Finish What Ya Started" with a story about writing songs in the middle of the night with Eddie when they used to be neighbors, then playfully quoted the legendary spoken-word interlude from Dave’s "Panama."

Sammy’s outfit is less of an overt Van Halen ripoff than Dave’s, at least from the look of it: guitarist Victor Johnson is a black dude with a shaved head, and bassist Mona was nicknamed the "first lady of rock" by Sammy. Sammy and Mona sang a gorgeous duet on "Eagles Fly," a ballad from his solo songbook that blossomed into a searing guitar solo by the Red Rocker himself. With that tender moment out of the way, the band started another volley of rock that culminated in Sammy’s smashing a huge tequila-bottle piñata over the stage during "Más Tequila."

Sammy brought the party to a raucous close with "Dreams," which kicked off with a shower of confetti and synthesizer. It’s one of the few Van Hagar songs even Roth devotees can get into — but by that point, there were no more partisans. As the on-stage fan-club members climbed down from their perch to dance next to the band, Sammy had one last thing to say: "We’d like to thank Diamond Dave for playing with us tonight. It’s been a fuckin’ great show." And for one moment, all was right in the oft-troubled Van Halen universe.

Sammy Hagar and David Lee Roth perform this Wednesday, August 28, at the Tweeter Center in Mansfield. Call (508) 339-2331.