In memory of Anwar Sadat, guest conductor Max Rudolf opened last night's National Symphony concert with the addition of the Air from the Third Suite of Bach. There was special significance in the tribute, since only last year the orchestra's music director, Mstislav Rostropovich, flew to Egypt to play a cello recital for the late president and his wife, Jihan Sadat.

The memorial music gave way to music of the utmost gaiety as pianist Walter Klien joined the reduced orchestra in Mozart's Concerto in F, K. 459. If the opening movement is reminiscent of the grace and charm of Almaviva's countess, its cadenza, sparkling in Klien's fingers, was sheer Papageno. This parallel was even more startling in the finale, with its frequent repetitions of the very notes on which Papageno sings his name in "The Magic Flute," which Mozart wrote seven years later.

Klien's playing is full of joy. He offered exquisite phrasing and sound and the beauty of style that gives this concerto its unique fragrance. Such playing is rare, and Klien is one of its few purveyors these days.

Rudolf and the musicians, having provided ideal accompaniment for Mozart, turned to weightier matters in the Bruckner Fourth Symphony, with a performance that was good but missed greatness for a variety of reasons. The kind of security needed in the almost secretive opening was not there; solo instruments throughout the orchestra were often in less than top form; and the tone was sometimes a touch on the raw side. Balancing these factors were many beautiful episodes conveying the work's grandeur. In the repetitions tonight, tomorrow and Friday, things may well move to a higher level.