Last night marked a historic occasion in the Kennedy Center Concert Hall and a significant breakthrough for Mstislav Rostropovich. He has conducted many mixed Russian and Viennese programs since become the music director of the National Symphony Orchestra in 1977, but last night was the first time he made the Viennese music sound more exciting than the Russian.

He was greatly assisted in this effort by Ludwing van Beethoven, marginally by Wolfgang Amadeus Mozart, and enormously by an oorchestra that recognized the occasion's potential and rose to it splendidly. The essential music was the "Eroica" Symphony, Rostropovich's material for the finest Beethoven performance I have heard him give.

It was part of a clevely designed program that also included Mozart's tiny overture to his opera "Bastein und Bastienne," composed when he was 12 years old, and 12 contredanses by Beethoven composed some time before the "Eroica," his Third Symphony. Both of these works have thematic material that is echoed in the "Eroica"; Mozart's theme (undoubtedly by pure coincidence) in the first movement and Beethoven's dance melodies (certainly with deliberation) in the variations of the finale. In this juxtaposition, the minor works (which are very minor indeed) serve neatly to show the difference between music that is merely pleasant and music that is not only great but also revolutionary.

The "Eroica" is the cornerstone of the repertoire in which Rostropovich is most at home, the beginning of the modern era in music and the grandfather of the symphonies by Prokofiev and Shostakovich that bring audiences to their feet when Rostropovich conducts them. Last night, his Beethoven excited the "bravos" and the standing ovation. But it was not a case of the conductor transforming the composer to Ludwig van Beethovenovich, something he has done, approximately, in the past. This time, the conductor became Herr von Rostropovich, which is as it should be. His "Eroica" marked no interpretive advance beyond Toscanini's (if such be possible), but it was completely idiomatic, beautifully controlled, carefully thought-out in every phrase and nuance and in its total structure. Above all, it had the special Rostropovich excitement -- the tingle in the Concert Hall's atmosphere that makes you remember one of the specialized meanings of "conductor": a medium for transmitting electricity.

The two minor works showed another side of his broadening skills as a conductor -- a growing ability to do justice to music that is not in his native idiom and not earthshaking. These bright, delicate little pieces have a deceptively simple style that can make a conductor seem silly if he approaches them witn any pretensions at all. Rostropovich gave them exactly the brisk, crisp, straightforward performances they require, and they were delightful in their own way.

Amid the charm and the greatness of the Viennese music, Prokofiev's First Violin Concerto was rather overshadowed -- by no means an easy feat, even for Beethoven. It is a dazzling, acrobatic work, full of compelling, exotic color and heart-tugging, romantic melodies that rise up only to be swept away on tides of self-conscious brilliance. Soloist Anne-Sophie Mutter, who is no longer a prodigy but (at 20) still very young, seemed not quite at home with the music -- not in terms of technique or interpretation but of dominating it, projecting it, tossing it off with confidence and aplomb. What her performance lacked last night was not musicianship but presence -- something that she may develop in repeat performances. Rostropovich's collaboration with her was knowing and empathetic.

As usual, during the standing ovation after the "Eroica," Rostropovich shared the applause with the entire orchestra, bidding its members to stand, section by section, to acknowledge the well-earned applause. But last night, before this gesture, he marched to the back of the stage, pulled Fred Begun from his place behind the tympani, and kissed hiim emphatically on both cheeks. It was a typically thoughtful gesture to a player whose contribution had helped significantly to make the event so exciting.