The mature skills of pianist Eugene Istomin and the warm sound of the National Symphony Orchestra conducted by Mstislav Rostropovich were joined to create a fine performance of Brahms' Piano Concerto No. 2 at the Kennedy Center Thursday night.

Istomin chose a slow, rather meditative tempo for the opening allegro non troppo. This was at first disconcerting, but the payoff came later in the movement (and even more in the wonderful allegro appassionato that followed), when power and substance grew inexorably out of the wealth of deliberate detail. Also excellent were John Martin's exquisite cello solo in the andante and Istomin's gentle, glistening treatment of the final, sublime allegretto grazioso.

The performance of Rossini's Overture to "La cambiale di matrimonio" was rather flat, partially due to the work itself, which only hints at the composer's later wit and dramatic ingenuity.

The gentle but ominous adagio of Haydn's Symphony No. 100 ("Military") led into a peppy, somewhat underplayed allegro. Woodwind solos were excellent, especially the flute, oboe and bassoon, which made up a tiny, distant marching band. In the extended "Alla Turca" sections the percussion created a rhythmic background that grew into a compelling poignancy against the gentle harmonies of the strings. The presto was more sedate than sparkling, but the coda, with martial trumpets and stirring drums, built to an exciting climax.