Mitsuko Uchida, Royal Festival Hall, London

Mitsuko Uchida plays 20th-century music so astoundingly well, you wonder why she doesn't tackle even more of it than she does. She began her Festival Hall recital with an 80th-birthday tribute to Pierre Boulez: a performance of his early Notations. And she packed such fizzing energy and wit into each of the 12 tiny pieces that the whole set, one of his earliest exercises in 12-note technique, seemed totally rethought. Orchestrating the set (five of them have been finished so far) has become one of Boulez's more protracted works in progress, and the piano originals have rather been taken for granted as a result, but Uchida showed what extraordinary miniatures they are - each perfectly focused and concentrating on a single potent musical idea.

They are not easy to play, but Uchida clearly hadn't planned this programme to make things easy for herself. Beethoven's Hammerklavier Sonata took up all of the second half, and that was separated from the Boulez by Schubert's C major Sonata D 840. The two-movement torso is one of Schubert's most curious and elusive piano works, with a first movement that migrates into a distant minor key for the second subject, and a second-movement andante full of mysterious, almost rootless transitions.

Uchida's playing creates a world that excludes all externals; this audience made that much harder, though, with a fusillade of coughing that began in the Boulez and climaxed in the second movement of the Schubert. At least most of it had stopped in the Hammerklavier - or perhaps it was just that Uchida's performance left the offenders with no breath to cough.

This was not by any means a perfect performance: there were moments in the outer movements that lost rhythmic definition and direction. But the sheer intensity was spellbinding: the opening allegro a fierce single span, the scherzo almost tossed away, the slow movement rising in a series of waves and the finale launched with a fugue subject as slippery as an eel. Totally compelling.