Gergiev Conducts the Kirov Orchestra Barbican Hall, London
The answers seem to lie in Valery Gergiev's hands. It's impossible to take your eyes off them. With or without baton (and this was a "with" occasion), it's the flutter of his fingertips around each and every phrase, as if providing vibrato for the entire orchestra, that first draws you in. The sound follows some way behind the beat, the delay affording his players time to contemplate, to hear the sound before they make it. This is Gergiev setting the air in motion, the better to accommodate the music. He is the most intense, the most spiritual of conductors, he appears to take music from the air, and his orchestra - the Kirov, from the Mariinsky Theatre, St Petersburg - have entered into the most extraordinary pact with him.

The shining halo of sound into which tenuous traceries of divided violins fashioned the Prelude to Act 1 of Wagner's Lohengrin on Thursday night was all about inner-light, a classic case of mind and substance over matter. Believe strongly enough in the quality of the notes and the reasons for them, phrase accordingly, and the sound will follow. There was a deeper resonance at work here - a resonance beyond anything that even the splendour of the Kirov strings and brass could account for. Gergiev and his players shaped and placed everything with such conviction as to make even one's wildest disagreements over this or that detail seem churlish. How often does one leave a performance of Tchaikovsky's Fifth Symphony thinking - so that is how it goes?

Most remarkable of all was the feeling that these very complex rubatos - the mechanics, if you like, of Gergiev's often very personal reading - were somehow written into the music. In a sense they were. In which case, why do they so rarely sound that way? Gergiev harnessed an incredible diversity of tempo and rubato here, none of it (except, perhaps, for the final bar of all) in the least counterfeit. So the extremes were a little more extreme than a close look at the score might suggest. This is extreme music. It wrestles with fate and emerges triumphant. That's what it's about. That's what Gergiev conveyed. But the outcome was by no means a forgone conclusion. There's the difference.

One detail must suffice: in the wake of fate's mighty pronouncement at the climax of the second movement (and how ardently Gergiev's violins swept into the return of the great second subject), there is silence, yawning silence, and a sequence of dispiriting pizzicatos. It can sound like a lame transitional device - so much sticky tape. Or it can leave you breathless with anticipation...

In the first half of the programme, Leif Ove Andsnes played Rachmaninov's Third Piano Concerto, and he could, one felt, have played it all over again in the second half. It was that kind of performance: relaxed, controlled, confident, commanding, eminently musical. Not so much as a whiff of post- Shine vulgarity. And for that, much thanks. In a sense - the traditional sense - it was less of a concerto, more of a symphonic kind of approach, meaning that piano and orchestra were so seamlessly integrated as to make the solo performance seem almost too modest, too retiring. In pursuit of the beautiful sound (and there was plenty of that - his "touch" in the slow movement was something to behold), Andsnes appeared to be holding out on the big moments. Why, even the first movement cadenza was well short of what one might call "the bathos threshold". Which was good, and yet not so good. For all that this was impressive, something was missing. Temperament? Perhaps Andsnes should have heard the Tchaikovsky first.

Valery Gergiev conducts two concert performances of Tchaikovsky's opera `The Enchantress', with the Royal Opera at the Royal Festival Hall, at 7pm tonight and on Monday. Booking 0171-960 4242