Mikhail Pletnev is the most objective and charismatic of pianists. You sometimes feel that his fingers are working independently of the rest of him, as if he were watching them perform an elaborate digital ballet. But then he launches his whole body into an explosively virtuosic passage.

It's a mesmerising combination, as he veers between cool detachment and complete engagement, and his performance of Rachmaninov's Rhapsody on a Theme of Paganini was the highlight of the National Symphony Orchestra of Washington's concert with Leonard Slatkin.

Pletnev far outstripped his accompanists in style, subtlety and substance. He made this hackneyed set of variations sound freshly composed. There was an astonishing range of colours in his playing, and he presented the opening theme with bald matter-of-factness.

But the detail of Rachmaninov's figuration in the early variations emerged with delicate brilliance. He made the Rhapsody sound like a masterpiece of impressionism rather than a late-romantic warhorse. The slow love song of the 18th variation built inexorably from a melancholic solo to a huge barrage of chords. And the final passage was a controlled explosion of technical virtuosity.

But there was more than jaw-dropping dexterity about this performance: Pletnev transformed the Rhapsody from an overblown showpiece into a work in which no note seemed extraneous.

Nothing in the rest of Slatkin's programme came close to this. The NSO were far from world class in a routine and sloppy account of Dvorak's New World Symphony. Slatkin's unimaginative direction and the orchestra's harsh and insubstantial tone made the piece sound tired and turgid.

Slatkin's brand of showmanship was much better suited to music by Leonard Bernstein and John Corigliano - he revelled in the kitsch spirituality of Bernstein's Chichester Psalms, with the Brighton Festival Chorus.

But even this gaudiness was outdone by the UK premiere of Corigliano's The Mannheim Rocket. The piece was inspired by the Mannheim Orchestra who, in the 18th century, pioneered the musical technique of increasing speed and volume (in other words, a crescendo).

Here, the orchestra set off in 12-note chaos, and jetted through a multitude of references to the classical tradition, before plummeting back to earth. The NSO relished the work's extravagant orchestration. But the music's in-jokes crashed and burned, just like the rocket they depicted, thanks to Corigliano's heavy-handed and unsubtle scoring.