Gustavo Dudamel's star has risen so high and so fast that at times it seems as if a large part of the future of orchestral music as a commercially viable art form now rests on the Venezuelan's slim shoulders. Almost overnight, the 28-year-old conductor has become the Barack Obama of classical music - for struggling orchestras around the world he is now, Obama-like, The One. But is he really as good as the hype implies? One senses that the sceptics are poised to try to burst his bubble.

On the strength of this electrifying concert, Dudamel will certainly do very nicely until anything better comes along. In years to come, this will be the concert that is remembered for an astonishingly vivid and exciting performance of Mahler's fifth symphony that had a capacity South Bank audience on its feet. But, in many ways, what marked Dudamel out as the real deal was the subtle and responsive accompaniment he coaxed from the Philharmonia for Emmanuel Ax's wise and characterful account of Mozart's G major piano concerto K453.

In the Mahler symphony, the Philharmonia quite simply played out of their skins for Dudamel. True, his supercharged approach is not the only way of doing Mahler - though it certainly suits this symphony. And I am sure there will be many who dislike his Leonard Bernstein-like cavortings on the podium. But music is a performance art, and anyone who can get the violins to play with such bite, the cellos with such expressivity, the brass with such potent phrasing - in short, the whole Philharmonia giving their all - gets my vote. Twenty years ago, with the Vienna Philharmonic, Bernstein conducted this very symphony in London in one of the greatest concerts he ever gave here. On this evidence, Dudamel is the new Lennie.