In what singer Nate Ruess referred to as the biggest show of their career, indie pop stars Fun played a triumphant 16-song set to a sun-baked but exuberant crowd of 15,000 last night. Fun — the capitalization-averse trio composed of Ruess, Jersey-born guitarist Jack Antonoff and jack-of-all-trades Andrew Dost — is still riding high on-the-hog of 2012’s million-plus-selling sophomore album Some Nights. The album is a whiskey-doused tribute to all-nighters, lost loves, family and the beauty and pain of the morning after that connected with audiences both young and old. Their success is based on their ability to write sugary percussive anthems and put them across with vigorous live performances. The latter was displayed in full force last night. The band kicked off their show with a brassy and jaunty “One Foot” and followed it up with raucous first album fan favorite “Walking The Dog” — and it was on. Ruess was all smiles, bounding all over the stage delivering impassioned vocals and pumping up the crowd. Antonoff played May to Ruess’ Mercury, driving the band with his guitar and firing off the occasional stinging, crowd-pleasing solo. Dost played anything and everything on the stage that made a sound, bouncing dexterously from piano to horns without missing a beat. Ruess seemed especially moved by the crowd’s reaction to the band, and talked about how the first show the band ever sold out was in Philly, and how much the fans here meant to them.They delivered a standout performance of my-best-friend-floats-in-the-bottom-of-the-glass hymn “We Are Young” that created such a booming crowd sing-along that it undoubtedly woke anything sleeping in Fairmount Park last night. The set’s biggest surprise was a ballsy take on The Rolling Stones’ “You Can’t Always Get What You Want.” Ruess transformed Mick’s ode to fleeting love and casual sex into a song about knowing that true love travels on a gravel road and that life is about celebrating the good that comes to you. The highlight of the night came mid-set. After an explosion of confetti, a soothing breeze blew in from the right causing the colorful tattered paper to gently swirl around the band as Dost tinkled the keys of the piano delivering the opening notes of “Carry On.” It is their best work, an elegiac number that is part sea shanty and part Celtic prayer. The crowd was hushed at first, hanging on every syllable Ruess uttered, but as the song built to its thumping crescendo the levee broke and 15,000 thousand voices united with his. “We are shining stars / We are invincible / We are who we are / On our darkest day / When we’re miles away / So we will come / We will find our way home.” Exactly. — PETE TROSHAK