Down in the basement of Cadavra, a nightclub better known for its late-night DJs than introspective live sets, Joanne Robertson filled a sold-out room with strange and beautiful music. It was just her, an electric guitar, four pedals, a lyric notebook, and a broken ’70s Fender lying face down beside her.

She began by explaining with dry humour that her beloved vintage guitar’s neck had snapped in transit. The injured instrument stayed on stage like a silent companion while she played a very fine replacement. Despite the setback, her playing was exquisite: loose, searching, full of feeling. Her songs, unpredictable, mysterious, and never built on familiar pop structures, felt as though they were discovering themselves live on stage.

Robertson was a lovely presence, warm, funny, unguarded. Between songs she joked about the club’s low whir, saying “maybe it’s just the natural sound of a nightclub”, and somehow turned the techno hum of Cadavra into part of her music’s ambience.

She played mostly tracks from Blurrr, her beautiful new album on AD93, and as expected, held the audience captive with her mesmerising vocals and hypnotic guitar lines.

The crowd was hushed, perhaps a little over-polite at first, Robertson’s dry wit and broad accent maybe a touch too fast for the Madrid crowd. But gradually they softened and leaned in closer. The set was wonderful and flowed beautifully; later, after preparing the crowd that there would be just two more songs, she played them tenderly, then set her guitar down to warm applause. But the audience wasn’t ready to let her go and near-demanded one final piece. She leafed through her notebook like a DJ sifting through a large crate of vinyl for that all important final tune and chose “Heat” by long-term collaborator Dean Blunt, a fragile, hypnotic closer that became, for me, the night’s highlight.

As the lights came up, people smiled and exchanged quiet words of admiration before drifting back into the night, carrying with them the lingering reverb of her beautiful, distinct, and utterly unique sound.