You may never have heard of Peter Winter, but he irritated Mozart.

Born two years before Mozart, Winter enjoyed great respect during his life-time, lived 35 years longer than Mozart, and occupied a far more exalted post than any Mozart ever attained. Last night the National Symphony brought Washington its first hearing of a Concertino for clarinet and cello by this now-forgotten composer.

The Concertino is expertly written, a charming exercise in which both instruments play expressively in solo, duo and concerted passages. Sometimes they have to scramble in a way that arouses admiration. Since the soloists were Mstislav Rostropovich and the National's superb first clarinet, Loren Kitt, the solos could not have been more deftly or more persuasively handled. With Hugh Wolff conducting, the whole thing went with polish and gusto.

Wolff preceded Winter with an eloquent reading of the Brahms-Haydn Variations. He found ideal tempos for nearly every variant and built the finale to a proper climax. Where he might profitably improve the sense of the whole is in certain variations during whose course he makes ritards that interfere with the basic pulse. It continues to be a matter of keen enjoyment to hear and watch Wolff with each new appearance, and the orchestra's response is a high mark in his favor.

Rostropovich closed the program with a towering account of the Sixth Symphony of Prokofiev, arguably the finest of his seven. The outer movements are of unflagging energy, ingenious in scoring and, in the finale, achieve a marvelous sophistication in reminiscences of the Classical Symphony written 30 years earlier. The slow movement is one of the jewels in the Prokofiev crown. The performance from conductor and players was full of wonders.