Joanna Newsom, Royal Albert Hall, London

One fears slightly for a solo performer making their first appearance at the Royal Albert Hall, and even the most devoted Joanna Newsom fan could be forgiven for wondering how the delicate 25-year-old harpist and singer from California might cope at the venue where the true meaning of commanding so vast a space puts one in mind of giants such as Bob Dylan and Leonard Cohen.

At the Barbican earlier this year, people left Newsom's show wondering if they had ever had such a profound musical experience in a concert hall – but then on that occasion she had the London Symphony Orchestra as her backing band, whereas now she had only a guitarist, a violinist and a drummer for support.

The three of them formed a cordon around her, and after Newsom had come on stage, looked up at the 3,000 capacity audience, and said, "This is seriously amazing" – a rather banal observation given the gift for poetic expression that she demonstrates in her lyrics – it seemed she might need all the protection she could get. "This is a very large room," she said at the conclusion of her opening number, "Bridges and Balloons". "I was going get my phone out and take a picture, but I left it back stage." Oh dear.

Later on, a phone was delivered, and Newsom started clicking. A section of the audience waved back at her nervously, unsure if this was quite how one conducts oneself in the presence of divinity. Provided one could banish thoughts of Newsom's similarities to Reese Witherspoon's character in Legally Blonde – the thousand-watt smile and the general ditziness – it was easy to see why, on the strength of just two albums so far, her fey, child-like incantations and the other-worldly musical landscapes that her harp-playing opens up have had such an effect on audiences. It's music that conjures up a willow-pattern scene – both an idyll to escape to, and therein find solace, and at the same time a land of mystery and foreboding.

In an atmosphere bordering on the reverential, Newsom and her band produced a sound that was nominally folk, but in its evocations of sources as varied as Kurt Weill, Stephen Sondheim and Kate Bush was pretty much uncategorisable. The longer numbers were closer to the theme-variation-and-recapitulation norms of classical composition than they were to any pop conventions. The hour-and-three-quarters set comprised just 12 songs, of which "Inflammatory Writ" and "Book of Right-On", two melodic masterpieces from her first album, The Milk-Eyed Mender, were the stand-outs. If reports from the gods suggest that Newsom did not quite conquer the entire hall, she still confirmed herself as one of the most original and arresting talents of the moment.