Prokofiev's brilliant Piano Concerto No. 3 was an ideal composition to end the National Symphony's marathon weekend series at Wolf Trap, which included half-a-dozen major piano concertos and an equal number of purely orchestral works. With pianist Horacio Guttierez, the music's very demanding solo part was in good hands; scales and arpeggios rippled from the keyboard with lightning speed and superb control. Guttierez and conductor Hugh Wolff seemed completely compatible, and both clearly relished the music's mercurial changes of style, from Chopin-like sentimentality to brash parody.

The orchestra did not manage to sound very interested in some segments of Borodin's "Polovtsian Dances," though the percussion section had a fine time when it took the spotlight. But when the program reached Prokofiev (who is becoming one of the orchestra's specialties), the NSO began to sound like an ensemble that aspires to be the world's leading Russian orchestra. Last night, only the aspiration could be heard -- not the level of achievement that was reached last season in "Alexander Nevsky" and that should be reached next season in Shostakovich's 14th Symphony. But in such a rushed, busy weekend, it would be unreasonable -- or at least unrealistic -- to expect more than the bright, well-paced interpretation that this concerto received last night, with some particularly enjoyable work from the brass and woodwinds.

In the first half of the program, Chopin's Piano Concerto in F minor was replaced with Schumann's in A minor -- a net improvement in programming, though the orchestra played it like a last-minute substitution. For Guttierez, it was obviously a familiar and favorite work, and he performed incisively, often brilliantly and with a fine sensitivity to the music's shifting moods.

The beginning of the program, Rossini's overture to "L'Italiana in Algeri," offered people on the lawn (where the vast majority chose to sit) an unusual opportunity: the chance to observe conductor Wolff leading the orchestra without any sound to divide their attention. After a couple of bars, the sound system tuned in -- at first a bit tentatively but then with a decent level of volume and balance -- and the evening proceeded without notable mishaps.