It is a pity that the Vienna Philharmonic and Leonard Bernstein could not bring us some of their superb Mahler during their two weeks here. In lieu of that, however, Mstislay Rostropovich and the National Symphony are graciously doing their best this week to fill the gap with the orchester's first performances of the Mahler Seventh Symphony.

The work is an appropriate choice for the occasion: first, because it displays the orchestra at its newly hewn best; second, because it is the last of the three enormous works Mahler wrote during his decade as the Vienna Opera's director and, third, because its current repute results largely from the proselytizing of Bernstein, who was present for last night's concert.

Rostropovich and the orchestra have been rehearsing the symphony -- in part, at least -- for more than two months, and it shows. In the ceremonial outburst that opens the last movement, for example, the tympani are followed by the brass, which are followed at full speed by the hurtling strings. Last night the music was crystal clear, but in balance and articulation. And by reining in the sound a bit, much of the forcing of tone that has showed up recently with the orchestra was eliminated without sacrificing the grandeur.

Rostropovich's interpretation was splendid. The tricky switches from tempo to tempo that dot the two outside movements in particular were mostly well managed, especially in the last movement. The hypnotic moods of the three inner movements were less evocatively projected; the extraordinary melodic and orchestral effects of the second movement's "night music" were not voiced with much richness or rhythmic grace.

One splendid precedent: Both Rostropovich and, the night before, Bernstein limited their programs to emotionally exhausting 90-minute works without intermission. That should become standard with works of such scope.