Her songs are largely downbeat ruminations on lost love, anger and reclaimed power, delivered with the precision of someone who understands mood and dynamics so acutely that she can grab a near-capacity room of would-be revellers and quiet them using only her voice and nuanced, at times whisper-quiet electric guitar playing.

But then perhaps her choice of intro music speaks of the contradiction that is McMahon. For while her songs brood with a noir, indie-rock intensity, she can’t help but smile as the audience sings along to last year’s Hottest 100 favourite Slow Mover. Her between-song banter is so natural, gracious and witty that even though her music basks in darkness, onstage there is nothing but light.

For an artist with only a handful of songs in the public domain – her debut album is due in the coming months – McMahon seems utterly at home in front of nearly 1000 people. She seems genuinely surprised at how full the room is, but she should be more impressed by how attentive people are during songs they’ve never heard. Granted, the attentiveness wanes slightly towards the end of the set, but time and more material will soon solve any such pacing issues.

At one point she’s joined by Canadian support act Leif Vollebekk for a cover of Bruce Springsteen’s Atlantic City. Its sparse and desperate mood matches that of her own music and yet this evening is nothing but uplifting. To watch McMahon and her two-piece backing band tease, stretch and ride the dynamics of Push is to witness an artist who is clearly capable of great things.

And tonight was one of them.