This week's concert by jazz pianist Brad Mehldau was one of the finest I've ever heard, with the leader in memorable form and his colleagues - Jeremy Brown (bass) and Stephen Keogh (drums) - providing beautiful support.

By the exalted standards Mehldau has already set, the opening performances, on a couple of his originals, though excellent, were really a warm-up for the pleasures that followed. These began with delicate examinations of a ballad, For All We Know, and continued with a blistering excursion through Coltrane's difficult Countdown, in which it seemed every facet of the piece was subjected to rigorous scrutiny, disassembled and the fragments made to coalesce into a new whole.

If that was good, what emerged in the second set was absolutely exalted. On The Way You Look Tonight he used a favourite device - playing at half the tempo of the rhythm section - to create tensions which he then exploited brilliantly, again managing to make seemingly disparate, fragmented runs hang together with inexorable logic. But the finest moment of a great concert was a superb Moon River; after a lyrically gentle handling of the banal theme, he built a new, improvised melody, even stronger and more personal, that had the edge-of-the-seat feeling of beauty in the act of being discovered.

After that, things could hardly be bettered, but a lovely Mehldau waltz, At A Loss, was no let-down, while Young At Heart - a piece every bit as banal as Moon River - almost equalled the evening's high point. Beginning with piano against two tinkling clockwork toys (yes!), it modulated from gently funny, to poignant, to a dramatic wail against fate, to final acceptance; every bit as moving as Moon River. He also produced a swinging, laid back Nobody Else But Me which both guyed and renewed the material and showed again what a marvellous one-off he is.

The history is there - you can hear bits of past masters, like Monk, Evans, Garland and Newborn - but what he does with them is pure Mehldau. It was a privilege to be there.