Last night's concert at the Kennedy Center by the Philadelphia Orchestra under Riccardo Muti was one of those giddy experiences of which only the very greatest orchestras are capable -- and only when they are playing at the peaks of their powers.

The program was extraordinarily demanding -- one that would take most orchestras several weeks of rehearsals to sustain at a proper level.

The program was also beautifully balanced -- Verdi's overture to "Luisa Miller," Copland's Third Symphony and Beethoven's "Emperor" Concerto, with Alfred Brendel the pianist.

Each is a basically affirmative work ending in a blaze of exultation. But that did not result in monotony, because each arrives at that point through a different route -- Verdi with a sad lyric theme that is transformed into victorious triumph at the end, Copland in the musical language of "Rodeo" applied to the European form of the four-movement symphony, and Beethoven in the unprecedentedly large scale of the "Emperor."

Each requires great reserves of energy to keep its momentum going. The Philadelphia has reserves that seem almost limitless.

This was most apparent in the Copland, with the main line so often in the high brass, often at the most formidable decibel levels -- a work that reaches its ultimate sonic moments in the celebrated "Fanfare for the Common Man" that opens the last movement. Powerful as the sound would get last night, though, it was never less than lovely.

It might never have occurred to one that the Italian Muti might turn out to be a superb Copland conductor, but that is exactly what he was. Those shifting moods -- the ambivalant shadows of the opening movement, the extraordinary gusto of the second, the mystery of the slow movement -- were stated with specificity and feeling. There was none of the rigidity that one has heard from Muti at times. He obviously adores the work -- which is probably the greatest American symphony. And so does the orchestra, which played with breathtaking virtuosity.

The Verdi was similarly electric. And the "Emperor" -- well, Brendel is one of the great Beethoven pianists of the day, and no one plays this work with a surer combination of directness and subtlety.

This concert was one of the most impressive events of the season.