CLASSICAL MUSIC Peter O'Hagan Purcell Room Ian Pace Conway Hall, London

O'Hagan and Pace: not another comedy duo, but two English pianists whose recent London recitals interestingly highlighted challenging composers of different generations. Peter O'Hagan's extraordinarily demanding programme at the Purcell Room on Tuesday began with two Stockhausen piano pieces - Klavierstuck IX (the one with the repeated chords) and Klavierstuck X (the rarely heard, large-scale one with clusters and glissandi, played with bandaged hands) - and continued with three Ligeti etudes.

O'Hagan clearly has a technique fully equal to Stockhausen's punishing demands. Playing both pieces from memory, he was able to shape individual gestures - in which he proved as alert to sonority as to the torrents of notes in No 10 - and to control complete spans of music with a natural feel for their drama as well as commendable clarity. The same applied to the Ligeti, and to the concluding Out of Doors suite by Bartok, in which more traditional pianistic virtues could be appreciated.

But the special feature of his programme was the performance of Boulez' Third Piano Sonata. Only two of this 40-year-old work's projected five movements were ever completed. O'Hagan gained permission to perform a version of the incomplete first movement, "Antiphonie", into which he interpolated the short, related "Sigle". The result was a four-minute upbeat - dominated by lean, mainly two-part writing, but quite dramatic and confrontational - to the completed "Constellation-Mirroir" and "Trope". O'Hagan's account of this aleatoric score - lasting 25 minutes, and concluding with a less familiar ordering of "Trope" - expertly handled Boulez's cunning exploitations of textural and dramatic contrast.

Richard Barrett's Tract, the London premiere of which concluded Ian Pace's Conway Hall recital last Thursday, just might be a masterpiece too, but it wasn't so easy to tell. Much younger than O'Hagan, though in some respects already better known, Pace seems an almost selfless musician with a rare dedication to challenging new work. It's therefore a shame to have to report that his carefully chosen programme included performances of Beethoven's Op 109 and Op 111 sonatas and Scriabin's 10th that revealed a curiously casual approach, demonstrating remarkably little thought about the sculpting of individual phrases or the shaping of whole movements.

The context was at least apt: Barrett refers to the slow movements of these Beethoven sonatas in the newly completed second part of Tract. Impatient, however, with conventional notions of expression, this talented and highly intelligent composer produces scores whose ferocious notational complexities can yield viscerally compelling results a million miles from more usual modern references to such sources. Tract teems with good ideas: the powerful opening, for instance, with its obsessive focus on the lower ranges of the keyboard. But the occasional startling displays of aggression - including some embarrassing theatrics (the banging of the piano lid at the end, for example) - seemed superficial, never earned. Pace's part in creating such an oddly unfocused impact with such wild means was hard to assess. But I'd like to hear what a pianist of O'Hagan's capabilities could do with Tract.