Lang Lang is a phenomenon, no doubt about it. This young pianist, barely into his twenties, has captured wide public attention with the brilliance and energy of his playing. His performance of Sergei Rachmaninoff's Piano Concerto No. 3 (the crushingly difficult "Rach Three" made legendary in the movie "Shine") at the Kennedy Center last night with the National Symphony Orchestra proved a dazzling -- and reassuring -- blend of bravura and brains.

I say "reassuring" because there had been some reason to believe that Lang Lang (he always uses both names) was lately expending rather too much care on being a virtuoso and not enough on being a musician. His extraordinary talent was apparent from the start of his career -- the boy (as he was then) had the manic ferocity of Vladimir Horowitz, the massive power of Alexis Weissenberg and the blooming piano tone of the young Van Cliburn. Was it churlish, then, to ask for more? In the past year or two, there seemed to be emerging an undue emphasis on flash and the sheer mechanics of playing the piano; the poetic introspection he had displayed in 1999 and 2000 seemed to be eroding as he quickly became famous.

And so it is a pleasure to report that Lang Lang's Rachmaninoff is all that one might have hoped -- meticulously plotted yet welling over with emotion, played with nobility and starry-eyed ecstasy. There was nothing ostentatious about the performance: Lang Lang simply moved in and conquered the work's flabbergasting technical and musical difficulties. Yet it never seemed a mere display piece: On the contrary, last night the concerto seemed to be only as challenging and digressive as it needed to be -- in fact, it seemed almost succinct (a word that has likely never been used in the same sentence as "Rachmaninoff Third" before). The late critic Claudia Cassidy once said that the "Rach Three" was "cheap unless it was magnificent"; last night it was magnificent.

NSO music director Leonard Slatkin had much to do with the performance's success: His steady assurance and essentially classical mien brought out the best in Lang Lang -- and Rachmaninoff.

The program began with three of Dvorak's "Slavonic Dances" -- the third week in a row that has featured selections from this set of works. One would have been quite enough -- three is like eating too many cream puffs -- and the survey is starting to feel obligatory (the centenary of Dvorak's death takes place next year). Nor were the performances anything to write home about： Slatkin and the players clearly had other things on their minds.

Jennifer Higdon's Concerto for Orchestra, for instance. This is a substantial and often exciting 35-minute piece in five movements that calls to mind, in passing, the music of Igor Stravinsky, Aaron Copland, Olivier Messiaen and Steve Reich without really sounding like any of them. The concerto, which received its world premiere in Philadelphia last year, maintains close ties to a tonal center -- there are dissonances aplenty but they seem decorative, rather than the main lingo of the piece -- yet it is distinctly modern in its sensibility. The fourth movement, scored for percussion alone, has some of the luminous mystery that is so winning in Carl Orff's "Musica Poetica," and the finale concludes with one of those propulsive, brashly energetic ticktocks that seem designed to impel listeners to their feet.

Higdon is a savvy, sensitive composer with a keen ear, an innate sense of form and a generous dash of pure esprit at her disposal. Her concerto kept a listener's attention throughout, due in part to the sense of pulse, heard or unheard, that is never far from the surface (even during rests, Higdon's music never quite pauses). Slatkin's interpretation seemed committed and fastidious: Here again, one sensed that another rehearsal would have been helpful, but the music came across.

The concert will be repeated tonight and tomorrow night at 8.