Since the cellist Steven Isserlis (50) and the pianist-composer Olli Mustonen (40) have been Wigmore Hall chamber-pals for decades, it was to be expected that this new tryst would gel. And since, despite their advancing years, they are both still kids at heart – the Finnish Mustonen was originally hailed as his country's Mozart – we could expect sparks to fly. And so they did, from the moment they set out across the oblique, shifting terrain inhabited by the cello sonata that Benjamin Britten wrote for Mstislav Rostropovich, as his impulsive first response to meeting him.
There are good reasons to watch these performers, as well as listen to them. While Isserlis keeps his face tilted heavenwards, as though to catch and transmit celestial inspiration, Mustonen does extraordinary things in the air with his hands. They weave arabesques above the keyboard before descending on to the keys; they act as a mute commentary on the sounds he is conjuring. He likens his hand-ballet to a tennis player's follow-through, arguing that it's all part of the encounter between flesh and (what was once) ivory; we hear, in part, with our eyes.
The ghostly dialogue that opens Britten's sonata was deftly done, as was the hurrying scherzo; the "elegy" was properly mournful, while the spirited march was redolent of Prokofiev. Mustonen's precise, emphatic pianism found its foil in Isserlis's mercurial flights. After which we got the sonata Mustonen composed for this instrumental combination in 2006: a big-boned work in which chordal progressions form the bedrock for some dramatic shifts in mood, texture and tempo. It's an entirely tonal work, yet it feels absolutely fresh; encouraging proof that the old classical seam is far from exhausted. The performance did it proud.
The second half began with Sibelius's "Malinconia", a desperately declamatory utterance that the composer is said to have dashed off in three hours, under pressure from grief for a dead daughter. It continued with Stravinsky's charming folk-song arrangement "Chanson Russe" and concluded with Martinu's first cello sonata, a doom-laden work written as the Nazis closed in on Czechoslovakia. So the encore was sweet relief: a piece written by the 16-year-old Mustonen that demonstrated what technical assurance he had – and what a melodic gift – even at that age. A young Mozart indeed.