If the main event in Kent Nagano's concert with the London Symphony Orchestra on Sunday was Shostakovich's Fourth Symphony, it was the supporting account of Beethoven's Fourth Piano Concerto that really caught the ear. The young soloist was Markus Groh, who in 1995 was the first German winner of the prestigious Queen Elizabeth Competition in Brussels, and was making his debut with the LSO.

He is clearly a talent to watch, although not everything about his reading was successful - sometimes he slowed the tempi too self-consciously to make an expressive point, while important details were occasionally overlooked. But the approach was fresh, the clarity and musicality of his phrasing impeccable, and his range of keyboard colour quite remarkable.

Everything - from the almost Horowitz-like depth charges in the extreme bass in the first movement, to the silky smooth cantabile in the second and the glittering cascades of the finale - was carefully considered, yet never seemed just calculated for effect. It was engaging, but also satisfying.

In a perfect world, Groh would have been partnered by a conductor willing to match his colouristic imagination and range of nuance. But, although wonderfully played by the LSO, Nagano's accompaniment was bland and generalised, without any real commitment. He was much more convincing in the symphony, for gigantic scores like the Fourth need the kind of clear-headed organisation that he can bring, while the orchestral response in the slow sections as much as in the cataclysmic climaxes was as thrillingly vivid as one would expect from such a world-class band.

This wasn't a view of Shostakovich that probed beneath the surface for subtexts. Nagano was content to let each movement build by accretion. But perhaps that matters less in this symphony than in the later works. In 1935, when he began composing it, Shostakovich had yet to learn the necessity of hiding his real feelings; everything is on full show in the Fourth, assembled in sometimes surreal juxtapositions. Nagano did not always bring out the element of the grotesque as sharply as some interpreters, but he certainly made sure the whole edifice exerted a powerful effect.