"Thanks for coming to my local and having a pint with me," said Tori Amos, another American pop singer who, after several years' residence in England, has a self-conscious grasp of the lingo. But comparisons with Madonna end there – at least as far as this gig was concerned. Where a Madonna show is designed for shock and awe, the first of Amos's two nights at the Hammersmith Apollo was an introspective affair, wholly focused on the woman and her piano.

Her latest album, Abnormally Attracted to Sin – recorded at the Cornish farm where she has lived for nearly a decade – returned Amos to the Top 20 last spring for the first time since 2001. Whimsical to the last, she didn't play much of it tonight. Of the handful of songs from the album, a jazzy Lady in Blue made the greatest impression, as almost the only deviation from the lush, piano-led poppiness that defined the rest of the set.

As a couple of hours' listening proved, there was room for a good deal more deviation. Amos's songwriting has become impenetrably ambiguous, and as a performer, she's equally enigmatic. Seated between a piano and portable keyboard, her flowing vocals more a stream of sound than actual words, she seemed a long way away. Wherever she was in her head, it wasn't west London, and while inscrutability may be a prime Amos selling point, it's not one of the building blocks of a great gig.

Characteristically, her set list had been decided at the last minute, so along with the familiar (Cornflake Girl, Winter) was the unfamiliar (Pancake, Raspberry Swirl), all sung with barely a pause in that intense, fluting voice. Impressive? Sure. But as Amos played on and on, and songs blurred into each other, you wished she would return from the distant planet she was on.