The Black Keys , Weezer  and Avicii  closed out the first night of the 11th annual Austin City Limits Music Festival with packed performances Friday, as thousands of fans braved the fall heat to kick off the weekend.
Austin's 351-acre Zilker Park played host to 45 musical acts to start the festival, including Florence & the Machine , Delta Spirit , the Afghan Whigs , Esperanza Spalding  and the Wombats .
The Black Keys Headline, Fill Zilker Park
Closing out a summer full of festival dates, the Black Keys played almost 20 songs during their 75-minute set as Friday night's headliner. Fans filled three stages' worth of space at Zilker Park as the Keys got things going with "Howling For You."
Heavy on the band's Grammy-winning 2010 album, "Brothers," the Keys played "Next Girl," "Tighten Up," "She's Long Gone," "Ten Cent Pistol" and "Everlasting Light" from their sixth studio album. Not forgetting their most recent collection, "El Camino," the Ohio duo played "Lonely Boy," "Gold on the Ceiling" and "Little Black Submarine," as well as older hits like "Your Touch." They closed out the night with "I Got Mine" before fans flooded out into the Austin streets.
Weezer Sticks to the Hits
Kicking off a 15-song set with "My Name is Jonas," the nerdy alt rockers gave the crowd a taste of their old and new hits -- including "Buddy Holly," "Memories," "I Want You To" and "Island in the Sun." During "Dope Nose," a fan joined frontman Rivers Cuomo onstage to dance along before the band performed the ever-popular "Beverly Hills" and "Pork and Beans." Finishing off the 60-minute set with "Sweater Song," Cuomo flashed one last Weezer hand sign to the crowd, made up of mostly 20-somethings who had been singing along and swaying nostalgically to the music they grew up on.
EDM Kept the Crowds Dancing All Night
Avicii owned the night with his "Teenage Wasteland" and "Fade into Darkness" remixes, supported by trippy lights and dance-worthy beats that had the crowd bouncing late into the night. Although their sets were on opposite sides of the park, Avicii's bass could be heard as far as the Black Keys' stage.
"It's a beautiful day. Let's boogie," A-Trak told the crowd earlier in the day before jumping right into his dance beats. He got the daytime festival-goers ready with "Big Bad Wolf," "Heads Will Roll" and his take on "Jump On It." Fans waiting for the Weezer set jammed as bikini-clad gals and shirtless gents did their versions of the "booty bounce." The DJ's set went a couple minutes long, leaving Weezer's Rivers Cuomo to kick around a soccer ball on the neighboring stage as he waited.
Delta Spirit Vocalist Trips and Falls, But Rocks On
California quintet Delta Springs put on a show for its mid-afternoon crowd, which stood out as the day's largest until the after-work masses made their way to the park around 6 p.m. If the band's indie rock sound and frontman Matthew Vasquez's killer vocals didn't catch the audience's attention, Vasquez's antics certainly did. The vocalist was bouncing around so much that he tripped over the amps and fell backwards during "Idaho," but he continued the song without missing a beat. Not one to be deterred by a misstep, he then started to climb the railings on the side of the stage during "Trash Can."
Afghan Whigs Rock Covers for Another Reunion Show
Attracting a slightly older crowd, the Afghan Whigs incorporated covers of "Who Do You Love," Frank Ocean's "Lovecrimes" and "See and Don't See" -- a song that marked their first new recording in five years back in May -- into their set. As part of the band's reunion tour, they also rocked with originals like "Uptown Again," "I'm Her Slave" and "Miles Iz Ded."
Buzzy European Acts Rule the Friday Morning Sets
Before noon on Friday, Liverpool rockers the Wombats took the stage, ready to entertain fans fresh off their first cup of coffee. "I know there was another band from Liverpool, but I don't think they did very well," lead vocalist Matthew Murphy joked. They sang to a large crowd for their 11:45 a.m. slot with "Our Perfect Disease," "Jump into the Fog" and "Let's Dance to Joy Division." Another U.K. band, Los Campesinos, also performed for the crowds Friday morning, while folksy sister duo First Aid Kit played "The Lion's Roar," among other songs, for fans waiting on Delta Spirit.
Mustaches, Vikings and Glitter Abound at ACL
It wouldn't be a music festival without attendees showing off some quirky fashion choices. Friday's assortment of festival watchers was more than the usual shirtless, bandana-donning bros. There were also male and female versions of "Where's Waldo," fans in Viking headdresses and beards, a gray-haired man wearing a loose (and we mean loose) leopard-print skirt, and so much more. Drawn-on mustaches made an appearance, as did a multi-colored tutus, Pharaoh hats, and a superhero with a glitter eye mask.
Fans Beat the Heat Watching Baseball
Mother Nature turned up the heat on Austin after last week's cooler weather, just in time for ACL fans to spend a full day under the sun. With temperatures in the mid to high-80s and only the occasional cloud to offer shade, crowds resting from the festival took in baseball games nearby at the Rock Island Hideaway, where two giant screens were set to ESPN and the MLB playoffs all day.
Austin Brings the BBQ
Representing the best of Texas barbecue at ACL Eats, Stubb's BBQ wowed hungry festival-goers with its jalapeño brisket tacos, while the Salt Lick's Sloppy Nachos -- slathered in cheese and chopped beef -- were another hit.
ACL continues through the weekend with select performances streaming live on the festival's YouTube page . Come back to Billboard.com tomorrow and Monday to see what other shenanigans happen this weekend at the Texas fest.
- Live