“They ain’t no pop band?” asked a man in his late 60s as he stood in the front row, watching Portugal. The Man’s Sunday Outside Lands set.

No one could blame him for his surprise — those who have only ever heard the formerly catchy “Feel It Still” (And who hasn’t? The song was used in commercials for the iPad Pro, Vitaminwater, YouTube TV and even the trailer for the “Peter Rabbit” movie) and nothing else by Portugal. The Man could easily think the band was a slightly better Imagine Dragons or Twenty One Pilots.

With half a billion streams on Spotify, “Feel It Still” is what brought Portugal. The Man into the mainstream, but the band refuses to stay there without kicking and screaming. The music video for the track is weird as hell, which the band acknowledged through its pre-show video — it’s a clip of Beavis and Butt-Head mocking the dancing baby head and frontman John Gourley’s mustache.

But then, of course, the cartoon idiots come to realize that the song isn’t stupid and that Portugal. The Man is “the greatest band in the world!” The on-screen visuals — the first of which was the endearing statement, “We are not very good at stage banter, so tonight’s performance will feature some slogans written by our management” — went so far as to reassure fans at the end of the set that “Feel It Still” would be the closer: “Don’t worry, we are playing that song right after this,” the screen read, no song title necessary.

Live, all of the songs off the band’s most recent album — 2017’s Woodstock — sound less pop-like, free of studio retouches and finally allowed to be pure, hard rock headbangers. If Portugal. The Man appeared cocky about that, the band was. But maybe that’s all part of its rock “persona.” If anything, as arrogant as the text of the performance’s psychedelic visuals may have been, the band’s playing was good enough to warrant it. The group walked out to Pink Floyd’s “Another Brick in the Wall, Part 2” and later covered the Rolling Stones’ “Gimme Shelter,” and, perhaps shockingly for those who only knew “Feel It Still,” it aced both with a natural flair.

But older fans had no doubt. Portugal. The Man performed all of its bests from 2013’s sound-defining Evil Friends, reveling in the richness of “Modern Jesus” and “Purple Yellow Red and Blue.” Whether members of the crowd were die-hard fans or experiencing their first romp with the rock band, long after the set ended, they could feel it still.