In 1994, a 17-year old Russian-born pianist named Konstantin Lifschitz had the temerity to issue a recording of Bach'sGoldberg Variations,which won him international attention and a Grammy nomination. Thirteen years on, he appears before a packed Wigmore Hall to meet the still more formidable challenge of unfolding the entire Book 1 - 100 minutes of florid and densely contrapuntal writing in all 24 keys of Bach'sWell-Tempered Clavier.

Bach himself would never have imagined such a presentation. His 24 preludes and fugues were designed primarily as teaching pieces, and ordered to demonstrate the advantages of a particular kind of tuning. And under drily didactic or ploddingly reverential fingers, an integral performance can be something of an endurance test. Yet here there was never a dead bar.

In part, this was due to Lifschitz's sovereign technique, with scarcely a finger slip or lapse in concentration the entire evening. Variations of touch, tone and pedalling were not only sensitive, with bell-like upper lines and beautifully weighted chordal sonorities, but almost invariablyfunctional, highlighting structural change. Indeed, Lifschitz seemed so technically secure that he could risk rethinking, rephrasing and re-expressing the music even as he played it.

Sometimes he did surprising things that one felt might seem more questionable on repetition: suddenly switching the dynamic level from soft to loud in mid flow, say, to hold the attention through a long, densely worked fugue such as Number 20 in A minor. Or he might suddenly slow the tempo and haze the texture in pedal towards the end of a prelude such as the lilting Number 9 in E major. Yet one was generally convinced that the aliveness of his playing lay in the one-off nature of these nuances.

Indeed he gave us a demonstration. Returning at the end to acknowledge his ovation, he began to play again the familiar prelude Number 1 in C major. It was clear why. What, two and a half hours earlier, had necessarily sounded tentative, now bloomed and pulsed in a fullness and completion of feeling. It was the most magical moment in a deeply satisfying evening.