As the band start playing, it’s not immediately clear which one of them actually is Courtney Barnett. Two guitarists flank the drummer at either end of the stage, their faces obscured by shaggy brown hair. But then the one in the Choose Love T-shirt begins to sing in a languid Australian drawl about having a panic attack while doing the gardening, and the author of one of the year’s most feted records finally makes herself known.

It’s fair to say that Barnett is not in possession of a magnetic stage presence: she has a business-like manner that gives away her unease (the venue is “kind of scary”, she explains). After wryly and self-deprecatingly cataloguing her fraught mental patterns on her album Sometimes I Sit and Think, and Sometimes I Just Sit – in which she worries about everything from dying in her sleep to nicotine-infused apples – it would be incongruous if she were a swaggering performer.

Although her band’s peppy, countrified garage-rock provides a pleasant backdrop – and a gratifyingly thundering one on the defiant Pedestrian at Best – there’s no question that Barnett’s appeal lies squarely in her vocals. And while lyrics often end up indistinguishable live, she seems unwilling to leave that to chance: in the drolly titled but rather painful Nobody Really Cares If You Don’t Go to the Party, she replaces one particularly revealing couplet with a series of blahs. Despite being here in the flesh, you can’t help feeling that it is on record that Barnett is more fully realised.

For the encore, the support band Big Scary join in for a rendition of the Saints’ 1978 anthem Know Your Product. A busy stage and a scene-stealing sax man mean Barnett and her spiralling thoughts are pushed even further out of the picture. It doesn’t matter too much, though: once you get home, you know where to find her.

• At Wulfrun Hall, Wolverhampton, 27 November. Box office: 0870 320 7000. Then touring.