Rotterdam PO/Gergiev/Lang Lang, Barbican, London <!-- none onestar twostar threestar fourstar fivestar -->

Well before he takes over as principal conductor of the London Symphony Orchestra, Valery Gergiev is an increasingly known quantity in the city. What remains to be seen is the long-term chemistry. If it's anything like his rapport with the Rotterdam Philharmonic, where he's been music director since 1995, the heart of it will be perpetual surprise.

There's a well-established Russian sound about the orchestra's brass and woodwind, when needed, but what really distinguishes the music-making is freshness: a sense that, as every page of the score is turned, adventure awaits.

Their visit, part of Gergiev's current Shostakovich series at the Barbican, showed that, in this composer at least, vitality can be enough. How fortunate, then, for the Beethoven concerto, that the solo pianist should be one who shares the vitality gene as well as precise judgement. Lang Lang plays as though possessing a second brain dedicated to imagining infinitesimal gradations of sonority, and turning them into equally nuanced operations of the fingers. Just the first, unaccompanied chord of the G major concerto was perfection: firm, radiant, wondrously balanced, and continuing with a phrase of sculpted steel - the opening you dream of, and go an eternity without hearing.

As the music continued, its variety of tone and touch combined with Lang Lang's powerful sense of direction to create an extraordinary intensity, without recourse to pulling the tempo around. It was as though this young musician had already digested everything about the composer and taken it to a new, transcendent level of understanding, just as late Beethoven transcends early, and ideally matched to a work that hovers between the two. A thrilling experience, with which Gergiev and orchestra kept up, even if they sounded a bit rough at times next to such subtlety.

The Shostakovich symphonies, in their different way, were just as thrilling and visionary. The noisy No 3, which boasts a choral "May Day" ending stuffed with early Soviet optimism, is one of his wildest stream-of-consciousness inventions. Hardly anything recurs, it just turns into the next idea, though many ideas show up further evolved in later symphonies, especially the Fifth. Gergiev layered, accumulated and, where possible, shaded with the necessary ruthless onward surge, while the London Symphony Chorus sang their terrifying ode with exactness and fervour.

The enigmatic final symphony, No 15, had one of those Gergiev performances that gradually expand into a momentous, concentrated stillness. In this context, the quotes of his earlier works and deliberate misquotes of William Tell or Tristan und Isolde sounded like another stream of consciousness, just more maturely organised, like a gathering of threads from a life. The music goes in sections that link but don't communicate or evolve. Even at the end, the cross-references tick quietly over without connecting, and, in this affecting performance, at once world-weary and fresh.