"Everyone having a good time so far?" Arcade Fire frontman Win Butler asked the crowd. "Any festival where you can see My Morning Jacket and Lil Wayne is OK with me."
The band then launched back into its kinetic set with a powerful version of "No Cars Go" and the crowd resumed head-bobbing and fist-pumping en masse.
Bonnaroo is a four-day festival but it really gets cranking on Fridays. This year Friday was full of conflicts, with at one point The Decemberists, Ray LaMontagne and Florence & The Machine playing overlapping sets in different parts of the former farm that hosts the festival.
My Morning Jacket kicked off the jam-packed evening concerts with its new song "Victory Dance." A lone trumpeter called the crowd to arms before lead singer Jim James sang, "Hope to watch the victory dance/in the evening's setting sun" as dusk descended and fans bounced to the tribal beat.
The band is a Bonnaroo favorite known for epic shows on the grounds and rose from the smaller tents and stages to its first main stage appearance Friday night. James, who began the set in a pair of white faux-fur boots and a blue overcoat, his wild hair blown around by fans, was amazed at how far away the crowd stretched into the distance.
"I can't tell you what a magical wonder it is to be here tonight," James said. "This is surreal."
Arcade Fire, in its first appearance at Bonnaroo, raised the intensity a notch with a set showcasing the band's latest album, The Suburbs, which scored an improbable upset at the Grammys with an album of the year victory. It's a thoughtful album full of heavy rockers packed with heavy ideas.
It seemed to translate perfectly at Bonnaroo, where Butler moved around the stage, tossed a full water bottle into the crowd and knocked over a microphone before playfully climbing off down onto a riser to sing into the fallen mic.
The Montreal-based band kicked off the set with scenes from Spike Jonze's 30-minute short film based on the album, and launched into "Ready to Start" and "Keep the Car Running." By the time Butler's wife Régine Chassagne sang "Haiti," about a third of the way through the set, the crowd was mesmerized, swaying along on a Caribbean beat. Butler kicked it into another gear, shouting, "All right, you (expletive) hippies, let's do it!" at the start of "Month of May" and relentlessly kept the pace up.
"My brother (bandmate Will Butler) and I grew up in Houston and it's great to feel the proper humidity for once," a sweat-drenched Butler said.
The crowd, battered by temperatures in the mid-90s, groaned.
"Trust me, it's nice," Butler said. "It's really cold where I live."