This was Ewa Kupiec's South Bank debut, and the Polish pianist was obviously out to impress: she chose to end the concert with Stravinsky's Three Movements from Petrushka, apparently the only work the composer wrote that even he couldn't play. Yet for all the effort Kupiec expended on this and a demanding first half, it was the least showy work in which she made the greatest impression.

She began with Chopin's Sonata No 2 in B flat minor, its opening passage a churn of notes with spiky accents picked out in a way that left the rhythm unsettled. Yet she had the reserves left to create a sustained climax of surprising intensity, and the famous funeral march brought a steady crescendo that made the piano's frame ring. However, the fourth movement, elusive at the best of times, became here a shapeless scramble, blurred by her insistent use of the sustaining pedal.

Liszt's Funerailles was a good companion piece, and brought a vivid depiction of violent death as the music peaked, staggered and slowed. But again, the most involved passages found Kupiec's playing turning harsh and frenzied. And the bedazzlements of Petrushka stretched her to her limits.

Thank goodness, then, for Debussy's Children's Corner - technically a doddle next to all this, but providing a breath of fresh air, and a vehicle in which Kupiec's powerfully vivid musical imagination could at last take flight. If played whimsically, these pieces can seem slight, but Kupiec, approaching them with the earnest solemnity of childhood, caught them spot on, giving Jimbo's Lullaby a solemn, angular lilt and making Golliwog's Cakewalk into a loping knees-up. Her Paderewski encore, which went with a Polish swing, found her similarly relaxed - and none of the flamboyant works before it could quite match up.