There’s the problem: Z100‘s Jingle Ball isn’t really a celebration of the vast pop universe in all its tricked-out glory. It’s a Top-40 playlist come to life for the young and restless – heavy rotation hits only, please. And no costume changes! (Commercials for VitaminWater and Five Points College are OK, though.)

Its lineup isn’t necessarily made up of the biggest stars, but the ones that most effectively pervaded the airwaves in the past year or so. On this night, that meant Gaga, but it also meant Pitbull, David Guetta, Kelly Clarkson, LMFAO, Gym Class Heroes and Demi Lovato, all of whom are nothing if not eager to please. Gaga takes pop theater to a higher power, where challenging eyes and ears to the point that thrill and fatigue become inseparable, somehow, makes sense. No wonder the Jingle Ball and Monster Ball crowds don’t mix.

Gaga followed Pitbull and Guetta, who each play a vital role in their hits, but not the most vital. The superstar DJ shrewdly led fans through his radio and club smashes, from the Flo Rida- and Nicki Minaj-assisted “Where Dem Girls At” to the unabashedly romantic “Without U,” featuring Usher. “We have 15 minutes to turn this into the best party on the planet!” Guetta shouted jubilantly. “Let’s go!”

Guetta had thousands jumping by the end of his set, but Pitbull made the whole Garden shake. An MC less in the rap sense than the party one, he beamed his singing friends (Chris Brown, Enrique Iglesias and Usher, again) in via a projection screen and basically supported their recorded hooks with his excellent backing band and dutiful, exhausting performance. He danced, rapped, pep-rallied, cursed in Spanish and did whatever would hype up the fans, until he was soaked in sweat and as gravel-throated as Lil Wayne. It didn’t function much differently from a DJ set, but it burned a lot more calories.

The most at-ease performer of the night was Clarkson, but she didn’t suffer for it. The American Idol queen’s two instruments are at their best right now – her voice, dynamic as ever and lately channeling Tina Turner’s diva-rock sass, and her Southern charm, a welcome change after the creepy-older-guy vibe of LMFAO and Gym Class Heroes. Clarkson’s earlier hits, “Since U Been Gone” and “My Life Would Suck Without You,” are still her best, but her new album’s singles, “Mr. Know It All” and “Stronger,” held up just fine. She brought out Lovato for a holiday duet of “Have Yourself a Merry Little Christmas” and the former Disney star’s impressive range held up well next to Clarkson’s innate power.

In the face of so much crowd-pleasing, Gaga’s set was just the kind of jarring spectacle on which she thrives. Her set was a junkyard of ’tis-the-season signifiers: reindeer antlers, Christmas lights and bundled evergreens, which she sat in between during her set-opener, “Edge of Glory,” making herself barely visible to the audience (cue the earliest exits). She followed with her giddy first hits, “Just Dance,” “Poker Face” and “Bad Romance,” and ordered, “Put your paws up!” A few thousand obeyed, but it wasn’t exactly the cultish surrender you’d find at her own Monster Ball shows. “Judas” came next, a hyper-speed industrial number that faltered at radio and didn’t fare much better here.

Gaga moved on to a cover of “White Christmas” with a new verse that she had written herself. She explained to the crowd her reason for adding to the original. “I think it’s too short,” Gaga said. “Just when I get into it, it stops. It’s like a really bad orgasm.” Parents and tweens made their way out. “You & I” delivered, though, with Gaga’s piano pounding and barroom belting trumping everything that had come before it, as did “Born This Way.”

Then, a costume change – the cardinal sin – and by the time Gaga was singing her “Marry the Night” encore, cloaked in a hospital gown and confronting the audience with a blank stare, only the hardcore fans and truly curious remained. It’s a good thing she’s much more than a radio star.