Last night, ahead of Saturday’s concert at Hammerstein Ballroom, power-pop survivors Weezer played a tiny contest-winner’s show at the legendary P.C. Richard & Son Theater. And for anyone wondering how Rivers Cuomo — the same tortured recluse who wrote Pinkerton and used to spend his downtime getting degrees at Harvard — now fronts one of the country’s most consistent arena-rock acts, this gig was a perfect explanation: Apparently, at some point in the last decade, Cuomo has gotten incredibly happy.

Decked out in matching jumpsuits, the band hung back while Rivers hopped around the stage, mostly without guitar, clutching the mike like a kid doing a DMX impersonation (appropriate, since Cuomo still looks all of fourteen.) He bantered with the crowd (“There’ll be no requests in the House of Weez!”), made gleeful references to the Weezer snuggie, and generally pulled off some real-deal swagger. The brief set list ran through the two new singles, plus “Say It Ain’t So,” “Buddy Holly,” “Why Bother,” and — best of all — a cover of Coldplay’s “Viva La Vida,” with Rivers very visibly reading the lyrics. (Check it out here.) No, we don’t know why. But, as his swag-surfing dance moves demonstrated, we do know it made Cuomo happy.