SHAWN MENDES FANS HAVE A ‘BALL’ ON RANDALLS ISLAND

Shawn Mendes went to the Governors Ball one year and thought: “Damn, it would be really cool to be onstage.” On Friday he got his chance. Fans waited two hours to see Mendes — and they weren’t disappointed with the 19-year-old heartthrob’s high-energy set, which was nearly drowned out by a mob of squealing teens.

The “Treat You Better” singer (left) stole the show on the first day of the three-day festival on Randalls Island, held every year since 2011.

By the time headliner Jack White took the stage, the party seemed to be winding down.

The White Stripes star’s audience visibly shrunk halfway through his set, which ended nearly 10 minutes ahead of schedule.

White churned out popular songs from his venerable band for almost two hours, at one point waded into politics.

On “Icky Thump,” White screamed, “This one’s for you, Trump” after reciting the line, “Why don’t you kick yourself out? You’re an immigrant, too.”

Organizers expect 150,000 people will attend the music festival, with promising sets from rappers Travis Scott and Eminem yet to come, and a whole lot more music in between.

Fans at home can live stream Governors Ball all weekend, starting at 4:45 p.m. each day, on Twitter. The festival ends Sunday night.

Ella Torres and Amy Rowe