Last night's concert at the Kennedy Center by the National Symphony was supposed to have begun with Haydn -- the vigorous and imposing overture to his unjustly neglected opera "L'isola disabitata" ("The Uninhabited Island"). But instead, a bunch of unscheduled brass players slipped on stage and, as the conductor came on, blasted out a four-chord fanfare as a tribute to him.

This was one of the orchestra's ways of welcoming home after five years Antal Dorati -- for seven seasons its music director, the person who presided over the first concert in this very hall, and the man who -- as much as any single individual -- is responsible for what is most distinguished about today's National Symphony. He seemed to love the gesture.

But the real tribute to Dorati was the consistently first-class quality of the night's playing.

It is an axiom of music today that Dorati is the Haydn conductor (being, among others things, the only person to record all 100-odd symphonies, and in performances of rare grace). Last night one marveled at how, with a few modest rehearsals of the overture, he could imprint the elusive Haydn style on an orchestra that normally does not display it. Phrasing, especially in the strings, showed the most enchanting finesse and delicacy. Balances were perfection. And the music glowed with a sense of Haydnesque well being.

By contrast, to conclude the concert, the dark, portentous textures and noble proportions of the Brahms First Symphony unfolded expansively and majestically. Dorati had the details of this music so totally in the palms of his hands -- literally -- that he could concentrate almost entirely on the overall lines and, above all, the meaning behind it all.

Also on the program, which will be repeated today, tomorrow and Tuesday, was something even more remarkable -- the performance of the Concerto for Orchestra by Dorati's mentor and teacher, Be'la Barto'k. The composer called this five-movement work a concerto even though he could have labeled it a suite or even a symphony. The reason was that, along with being one of the most poignant compositions of the century, it is a dazzling display piece for the choirs and solos of the whole orchestra -- and it is incredibly difficult.

I've never heard the National Symphony play better. Those amazing metrical shifts that are at the rhythmic core of the piece could hardly have been more precise. Details like the trill in the opening phrase of the fourth movement were astonishingly accurate. But above all everything was steady as a rock, without sacrificing the haunting colors and moods of the Concerto. It was not surprising that Dorati could be a great Barto'k conductor. But one was truly taken aback that the National Symphony could be a great Bart'ok orchestra.

Some concert. Catch one of the repeats.