This is New York electropop outfit St. Lucia’s first year playing Austin City Limits Music Festival. You wouldn’t be able to tell, though, because they practically own Zilker Park after Friday’s set. Mayor Adler, get that deed ready.

This does not come as a surprise — Jean-Philip Grobler pulled out all the stops at South by Southwest this year. But the white-clad dandy, his mint guitar, his band and a potted plant on stage grabbed the crowd at the Miller Lite stage by the collective collar and wouldn’t let go. (For his part, Grobler’s collar belonged to a Sade T-shirt.)

St. Lucia performs on the first day of the 2016 Austin City Limits Festival on the Great Lawn at Zilker Park Sept. 30. 09/30/16 Tom McCarthy Jr. for AMERICAN-STATESMAN

Grobler worked the stage like an Olympic athlete, voice belting so impressively that you weren’t sure if it was him or the wind that was blowing his hair just so. On buoyant songs like “Dancing On Glass” and “Closer Than This,” which bubbled like a can of tropical-flavored La Croix, he was poised and polished, in a sweaty way. On “Love Somebody,” the traditional St. Lucia “diplomatic mission” brought the South Africa native out into the crowd into a garden of iPhones. In a set that was nothing but home runs, signature song “Elevate” turned the perfect festival party. Grobler screamed “EVERYBODY (EXPLETIVE) JUMP” in a way that really made a concert-goer appreciate a jump command that seems organic. He spun as he played, he walked backward as he played.

Austin, TX -A heavy crowd of fans gathered for St. Lucia’s set at ACL Music Festival on August 30, 2016. Suzanne Cordeiro for American-Statesman

The synthpop pot boiled over as the hour drew to an end. On show-closer “Physical” — well, accidental show-closer, as the band ran out of time for a mysterious last song they didn’t get to play — Grobler laid down, slapped the stage floor and slid on his knees. In a poised and polished ACL Fest debut, nearly the only flaws were the scuff marks on Grobler’s pants.