Drake Makes the Crowd Put in 'Work,' Plus 21 More Things You Need to See From iHeartRadio Festival Day 1

Christopher Polk/Getty Images for iHeartMedia

Drake performs at the 2016 iHeartRadio Music Festival at T-Mobile Arena on September 23, 2016, in Las Vegas.

U2, Sia & a surprise Miley Cyrus appearance are also highlights from the first night in Vegas.

Fans inside Las Vegas' T-Mobile Arena on Friday night (Sept. 23) for the iHeartRadio Music Festival were blown away by emotional and energetic sets from U2, Drake, Sia, Twenty One Pilots and more -- and we're only halfway through this thing.

Miley Cyrus Shows Off Her 'Rebel Yell' With Billy Idol at iHeartRadio Music Festival

But before we move on to Britney Spears, Sting and the rest of the Saturday night lineup, take a look at what you might have missed from night one of #iHeartFestival:

7:09 p.m. PT: Los 5 -- winners of the Macy's Rising Star competition -- kick off the show. The Latin pop quintet includes members from Mexico, Argentina and Brazil. Last year, the contest's winner was Voice alum Christina Grimmie, who was fatally shot at her Orlando concert this past summer.

7:42 p.m.: Billy Idol starts his set with a fiery bang, launching into back-to-back hits: "Dancing With Myself" and "White Wedding."

7:59 p.m.: And Idol really lights the night up when Miley Cyrus joins him for "Rebel Yell." "I'm singing with Billy f---ing Idol!" the new Voice coach yells from the stage.

8:10 p.m.: Newly engaged Bachelorette couple Jordan Rodgers and JoJo Fletcher announce country star Sam Hunt. JoJo told reporters backstage that she loves his music -- and so does friend and onetime romantic rival Lauren Bush, who is about to star on Ben & Lauren: Happily Ever After? with Bachelor fiancé Ben Higgins, premiering Oct. 11 on Freeform.

8:22 p.m.: Hunt turns T-Mobile Arena into his own personal "House Party."

9:09 p.m.: OneRepublic closes out an almost half-hour set with "Counting Stars," as frontman Ryan Tedder makes his way through the crowd to grab dozens of lucky fans' hands and take a few selfies.

9:27 p.m.: Sia offers one of her first showings of latest single "The Greatest" -- which she debuted live earlier this month at the Apple live-stream event -- and her performance-art soul mate Maddie Ziegler brings the video's Orlando tribute to life in a stirring dance.

.@Sia is the GREATEST! #iHeartFestival https://t.co/J1AS8Btckf pic.twitter.com/BpxtJ5CcCt

— iHeartRadio (@iHeartRadio) September 24, 2016

9:44 p.m.: While walking between the arena and the backstage press area, the crowds were momentarily held in a corral while mystery artists made their way through. It turned out to be U2 being shuttled to the stage area to get ready for their show-closing set.

9:49 p.m.: Twenty One Pilots show off the impressive roster of hits they have stacked up over the past year, starting with "Heathens" and running through "Stressed Out" and "Ride," of course.

10:08 p.m.: Frontman Tyler Joseph finishes the Twenty One Pilots set atop a dangerously small platform high above the crowd.

.@tylerrjoseph of @twentyonepilots went all the way up at #iHeartFestival! https://t.co/J1AS8Btckf pic.twitter.com/Rm090fvZB2

— iHeartRadio (@iHeartRadio) September 24, 2016

10:32 p.m.: Drake starts a set that spans nine of his songs -- leaning toward more recent tracks like "Controlla," DJ Khaled's "For Free" and Billboard Hot 100 No. 1 "One Dance" -- but he kicks things off (appropriately) with 2013's "Started From the Bottom."

ONE DANCE! @Drake is going hard at #iHeartFestival! pic.twitter.com/X7XcCCb9RY

— iHeartRadio (@iHeartRadio) September 24, 2016

10:44 p.m.: There was no surprise Rihanna appearance, but Drake still performs their joint No. 1 hit "Work," asking the ladies in the T-Mobile Arena crowd to fill in for RiRi.

10:59 p.m.: "Once again, Las Vegas, I go by the name of Drake. I'm from Toronto, Canada, and I appreciate you tonight."

11:04 p.m.: Sean Penn makes a surprise appearance as a presenter, introducing U2.

11:09 p.m.: U2 play the very Vegas-appropriate song "Desire," as fast-paced Sin City imagery (slot machines, showgirls, poker tables) flashes behind them. Things turn a little less flashy when Donald Trump appears onscreen and this sound bite is repeated: "What do you have to lose?" Finally, Bono asks the crowd that same question. "What do you have to lose? Everything," he says to wild applause.

11:44 p.m.: U2 performed an epic set of hits that included "Beautiful Day," "One" and "Pride (In the Name of Love)," but the one that stands out the most is the ballad "Every Breaking Wave" from 2014's Songs of Innocence. Bono thanks "brave DJs" for playing the song even though it might not have been the "right tempo."

11:56 p.m.: As "Still Haven't Found What I'm Looking For" wraps up and the lights stay dim, fans finally accept that there will be no encore (what more did you want from these guys?) when the iHeartRadio logo takes over the big screens.

.@U2 is still going strong at #iHeartFestival! pic.twitter.com/zg0ZVwXtvo

— iHeartRadio (@iHeartRadio) September 24, 2016