Pianist Daniil Trifonov brought breathtaking imagination to several pieces during the National Symphony Orchestra performance Thursday. (Alexander Ivanov)

After their brutal past week with “Der Rosenkavalier” and another heavy dose of Strauss due next week (his music taxes orchestra players like no other), the National Symphony Orchestra musicians probably breathed a sigh of relief at this week’s program of familiar and relatively easy repertoire.

The orchestra was guided Thursday by one of the world’s most genial and assured conductors, Rafael Frühbeck de Burgos, and it welcomed Russian piano phenom Daniil Trifonov, who was making his NSO debut in Rachmaninoff’s evergreen “Rhapsody on a Theme of Paganini.”

Frühbeck de Burgos, who is in his 80s, was noticeably more gaunt and frail than in his last appearance here two years ago. His gestures were strong and steady Thursday at the Kennedy Center’s Concert Hall, but had less detail and vividness than before, leading to general mushiness of ensemble. Some tempos, too, were too drowsy, particularly Debussy’s “Fêtes,” Manuel de Falla’s “Ritual Fire Dance” and in Respighi’s “Pines of the Villa Borghese.”

Still, the deep sincerity and musical authority drew committed playing from the musicians. In particular, Frühbeck de Burgos gave each diminuendo an expressive force that’s often missing at NSO concerts. And the strings were clearer and better-balanced than is often the case, as he insisted on re-seating them in the traditional array of higher-to-lower sections panning left to right, as former music director Mstislav Rostropovich had done.

I strongly protest performances of two-thirds of the Debussy “Nocturnes” (which are unfortunately common). The final one, “Sirènes,” calls for a women’s chorus — which should be easy enough to find in a town crawling with choirs — and the first two pieces require the last one for structural and aesthetic culmination. So this highly unsatisfying diptych was a bad start.

That was quickly dissipated by the Rachmaninoff. Trifonov, who is in his early 20s but still looks like a gangly, not-fully-grown teenager, is a marvel. There’s lots of show-and-tell in his approach to the instrument (too much for my taste), but close your eyes and there is a waterfall of musical thought underlying the virtuosity. The imagination he brought to the small cadenzas at the end of Variations XI and XXII was amazingly colorful, and the transition from the tenebrous Variation XVII into the sunlight of the famous Variation XVIII was — I don’t mind saying it — breathtaking.

After a vociferous ovation, his encore, Chopin’s Op. 18 Waltz, was perhaps too fussy, with a puzzlingly wide variety of tempos. But make no mistake: Trifonov produces as beautiful piano playing as you can hear today. (There was a run on his CDs in the lobby at intermission.)

The NSO had never done de Falla’s complete “El amor brujo” ballet, and it was a welcome addition, considerably enhanced by the lustrous mezzo Kelley O’Connor. Much of her part actually lies in alto territory, but the voice rang out down there, anyway. This is music that Frühbeck de Burgos knows down to his corpuscles, and although the piece drags a little in spots, it was enjoyable overall.

The concert ended with the Respighi’s surefire “Pines of Rome.” It is impossible not to be stirred by the Disney-like playfulness and thunder, with the brass making the walls shake at the end. The very nice solos by the principal trumpet (in the “Pines Near a Catacomb”) and clarinet (in “The Pines of the Janiculum”) compensated for a disastrous outing by the horns in the opening number.

Battey is a freelance writer.

The program will be repeated Friday and Saturday night.