Imogen Cooper 70th Birthday Concert, Wigmore Hall review - outwardly austere, lit from within

There are now two septuagenarians playing Schubert at a level no other living pianist can touch.

Imogen Cooper celebrated her 70th birthday on 28 August, and marked it at the Wigmore Hall last night with a two-interval epic, poised but full of inner fire and deepest pathos, not long after 74-year-old Elisabeth Leonskaja had touched the heavens playing Beethoven's last three sonatas in a late-night concert and joined with Liza Ferschtman and István Várdai in Schubert's two late piano trios.

Leonskaja has also programmed the Schubert triptych of the composer's last year in a single concert, and in one respect she will always have the edge. It may sound like pedantry to complain that like her mentor Alfred Brendel, Cooper shuns the exposition repeats in the first movements of the A and B flat major Sonatas. Sviatoslav Richter, Leonskaja's spiritual guide, on the other hand used to ask students who did so, "What? You don't love Schubert's music?" Last night gave the perfect reason why that seems like a mistake.

Cooper made the C minor Sonata, D958, seem more than usually sober and troubled, though full of sublime touches: the final abrupt resolution of the three-chord question marks in the Adagio, the upsetting pauses in the Menuetto swept away by a tarantella finale that seemed here less the usual dance with the devil, more anxious to will trouble away with a constant stream of notes, and paying for it in what came across as the work's biggest dark climax. All the more need, then, for the calm melody minutes into the A major masterpiece to reiterate its claim. Cooper (pictured below at the Arctic Philharmonic Chamber Festival in Svalbard earlier this year) played it so exquisitely that we wanted to hear it again in its original form, but that was forbidden. Never mind; the equally calm anchoring of the Rondo-finale weighed the balnce in favour of mortality, or the fear of death, temporarily overcome. Cooper never overdoesit in her special articulation to give space to a phrase, never forces the tone, though the biggest blitz of the entire trilogy, at the heart of the otherwise hypnotic-melancholy Andantino, had full impact.

It hardly seemed possible after the central panel that Schubert could take us further, but he does, in what is arguably the greatest of all sonata slow movements, the Andante sostenuto of D960. There is perfection in the way that profound sadness is finally transcended by a shift into heavenly major-key light, and it needs equal perfection, anchoring and inwardness in the playing. That Cooper achieved those qualities at the most profound level - the ideal of time becoming space - meant that the last two movements could seem superfluous: as in the "Unfinished" Symphony, Schubert seems to have said enough at the midway-point. Hyper-alertness and that unique diamantine quality Cooper's right hand brings to the upper register kept us hooked, though, to the headlong conclusion. For the bows, a standing ovation the Wigmore audience rarely grants, passionate devotion and gratitude, but no fuss. A place among the immortals is assured, but there are hopefully many more years of pianistic revelations to come.

• To be broadcast on BBC Radio 3 on Thursday 24 October
• More classical music reviews on theartsdesk

Watch Imogen Cooper's superb lecture on 'The Hidden Power of the Re-Creative Process in Music'