To see a capacity Festival Hall audience - more than 3,000 people - surge to its feet at the end of a classical concerto is a rare thing. This is London, not LA. But Sunday's concert was a unique and touching occasion: the final public performance by Alfred Brendel in the city in which he has lived for four decades.

And it was a stunning exit, too. Such is the affection in which this stooped, bespectacled, perpetually perplexed-looking figure is held that he could probably have played the Yellow Pages and received a standing ovation. Characteristically, he actually chose one of Mozart's deepest and most mysterious early piano concertos: No9 in E flat, K271. He then gave it the kind of interpretation that made one wish that he could be coaxed out of his self-imposed retirement at least once each year - just to remind the rest of us what integrity and profundity really are.

It was utterly unshowy yet mesmerisingly elegant and nimble; devoid of affectation yet packed with nuances that suggested a teeming inner emotional world. The outer allegros were mostly genial and light-fingered: models of intellectual and technical lucidity. But it was Brendel's handling of the great central andantino, and of the extraordinary minuet interrupting the finale, that truly astonished. The former became more and more anguished - the dissonant passing-notes, stabbing at its dark C-minor harmonies, seemed increasingly traumatised; the mood was stoic yet infinitely sad. If this was a farewell to the stage, it was a turbulent renunciation, full of mixed feelings, not a contented valediction.

And the Viennese minuet was even more remarkably delivered: almost as a recollection of how Brendel's immense personal journey had begun. As he caressed those evocative chords he seemed as close to being overwrought on stage as I have ever seen.

After that it wasn't quite silence. A wonderfully severe Bach chorale prelude, in Busoni's majestic transcription, was the final thing that Brendel played in London. Tonight, in Basingstoke, the same programme will be his last in Britain. Then he takes two Mozart concertos on a farewell European tour ending in Vienna in December. And that's it.

Haydn and Dvorák symphonies - with the Philharmonia and Charles Mackerras in scintillating form - provided suitably triumphant trimmings to the main event. Thanks heavens that the octogenarian Mackerras hasn't announced his retirement as well. He just gets better and better.

Editor's choice

• The 100 Best Films of 2008
• Hitler and the Downfall mash-ups
• Britney Spears: The Circus