Initially, when the band emerged from the wings of the stage to a roar from the audience, it was very hard to find Courtney Barnett. The quirky Australian indie rocker made her name as the Bob Dylan of millennial artists, and she looked the part in a plain white T-shirt and black pants. She was abrupt and unceremonious as she strode on stage, red guitar slung low around her hips like she was a bit player instead of the star attraction. She turned to face the audience, said “hi” and then launched headfirst into “City Looks Pretty,” the lead single from her latest album, Tell Me How You Really Feel.

As that album title implies, Barnett is all about realness. Projected behind her throughout the set was only a simple, unchanging graphic. There was no choreography, no flashy instrumental solos, no reverb on from mic, no adornment of Barnett’s famously flat delivery. Essentially, there was nothing at all to distract from the power and gravity of her most formidable talent — her songwriting.

Of course, in this setting, it was a lot more difficult to believe the apathetic persona she typically exudes through her work. Can one really take her seriously as she sings “I don’t know about anything” while demonstrating incredible control over her guitar and voice, simultaneously?

But irony, the most difficult ingredient of humor, is a well-known weapon in Barnett’s repertoire. Her plaintive wish in “Depreston” to not “be around all these coffee shops” even got chuckles from the audience. This theme was familiar to the caffeinated horsemen of the Bay Area gentrification apocalypse.

Her less celebrated skill is sincerity, whether it be admitting how she saves exactly “$23 a week” or how she’s “not that good at breathing in.” But at Treasure Island Music Festival, Barnett showed not just her clever side, but her genuine side as well. And with that, she sure did not disappoint us.