Hugh Wolff did it the hard way, conducting the National Symphony Orchestra last night at the Kennedy Center. He climaxed an all-Beethoven program with an outstanding interpretation of the Eighth Symphony -- perhaps the toughest possible test for a young conductor trying to make a strong impression on his first major appearance.

Any Beethoven is hard in such a situation; music-lovers know the music intimately, and they remember it in the performances of the world's greatest musicians; their judgments are likely to be harsh, and any attempt at originality can easily be labeled eccentricity.

Wolff's Eighth had all the difficult virtues -- the ones usually associated with conductors twice his age. It was clear, balanced, phrased with great sensitivity and accented with a special feeling for the music's uniquely warm, jovial personality. Some of the fast sections were a shade headlong, but within the limits of the composer's (admittedly controversial) metronome markings and the performances tradition. More important that that, it had the right lilt in its most zestful moments -- the feeling of Beethoven singing to himself as he makes his slightly erratic way home from a good party.

It was the best part of an evening that had many other good parts -- particularly when the music brought out the senses of lyricism and drama which are obviously well developed in this young conductor. The program opened with "Leonore" Overture No. 3 built carefully with a fine sense of climax after a slightly ragged first chord, and it reached a high point in the dramatic dialogue of the slow movement of Piano Concerto No. 4.

In the concerto, Wolff had a few mild disagreements with pianist Horacio Guttierez, who soloed brilliantly, and the first movement seemed less finely calculated than the others. But the orchestra responded sensitively to Wolff's clear, precise gestures and his interpretation (particularly after the first movement) was convincing.

Wolff is clearly a musician of great potential, and he has made an auspicious debut.