Mitsuko Uchida, Royal Festival Hall, London

Born and bred in Japan, then formed in Vienna, Mitsuko Uchida has spent so much of her life in this country that she now qualifies as a British national treasure. By her work with young musicians she's earned a different kind of fame: passionately opposed to the prodigy circus, she waits until maturer promise has revealed itself, then steps in with practical help. And her art is in permanent evolution: Bach, Beethoven, Schubert and Mozart may be her lifelong companions, but she's also drawn to cutting-edge modernism, with the reclusive Hungarian György Kurtág being her latest big – or rather, diminutively small – thing.

And what a match these two proved: the aphoristic brilliance of his music found in this fastidiously responsive interpreter its ideal conduit. In some ways Kurtag isn't "modern" at all, as Uchida demonstrated with his Jatekok ("Games"), which she scattered like gold-dust through her otherwise traditional programme. These pieces, which Kurtag has been elaborating all his life, range from beginner-level stuff to high virtuosity: sometimes lasting a bare 20 seconds, they suggest windows opening to let bursts of music out, before slamming shut again.

Schubert and Schumann framed this South Bank recital, but its core was a piquant amalgam of Kurtag and Bach. Each note in Kurtag's 43-second Antiphone in F sharp was like a pebble dropped into a pool, after which Uchida segued gracefully into the calm waters of Bach's "Contrapunctus".

Then came three more terse Kurtags – one playful, one plangent, the third a pedalled miasma – after which a Bach sarabande brought expansive release. Uchida then turned the decorated descending scale of Kurtag's "Play with Infinity" into a mysterious disappearing act: how will Radio 3's sound engineer erase the tumbling plastic mug that some idiot dropped during the last seconds of that brilliantly created illusion? The broadcast is on 9 April.

Uchida opened this concert with Schubert's grimly valedictory Sonata in C minor D 958, which, under her magic touch, became electrifying. The seeming waywardness of the impassioned opening movement here made perfect sense, and the second became a cosmic drama; in the hurtling final gallop, Uchida was all fire, wind and thunder. Rounding off the evening with the original, untamed version of Schumann's great Etudes Symphoniques, she reminded us that she, too, is a poet first and last.