Live performances of Brahms’s “Variations and Fugue on a Theme by Handel” are rare, and those who only know the piece through recordings may not appreciate its level of difficulty. The last two times I heard it in recital, the results were disastrous. In 2000 at the 92nd Street Y, Vladimir Feltsman navigated the variations well enough, but he got hopelessly lost in the complex fugue, eventually composing his own passages extemporaneously and arising from the piano bench at the piece’s conclusion loudly laughing at himself. And in 2004, the normally precise Murray Perahia juggled and struggled through an unfocused performance at Carnegie Hall.

This degree of difficulty is no accident. Like Liszt and Rachmaninoff, Brahms composed hard-to-perform pieces for the piano in order to preserve them for himself. Each of these three composers was a master technician with enormous hands; each made a living largely by his prowess at the keyboard. For mere mortals, these compositions are to be appreciated but not attempted.

On Saturday evening at Alice Tully Hall, the Naumburg award winner Peter Orth courageously opened his program with this labyrinthine masterwork. Mr. Orth is not well-known on this side of the pond primarily because of his decision to move to Cologne. Germany, in the early 1990s. He had previously studied at Juilliard and been a member of the artistic community at the Marlboro festival and the Institute for Young Performing Musicians in Guilford, Vermont, both under the supervision of Rudolf Serkin.

Mr. Orth began the Brahms with a stately rendering of the original theme, phrased and paced almost as if it were a throwback to Elizabethan times. His first five or six variations were jaunty in spirit and juicily arrhythmic in statement – metronome be damned. Technically these were fine interpretations with only the occasional wayward landing.

This pianist is careful to emphasize the individual variation as a unique organism, stopping after each for a moment of reflection. He constructed a marvelous build-up to the climax of the ultimate in the series, perhaps a little too dramatically impressive. Mr. Orth was unphased by the applause that greeted this strong conclusion – this type of interruption from the crowd did in Mr. Feltsman – and proceeded to sail through an intricate fugal construction of remarkable accuracy. Here he captured the grandiloquence of the architecture quite convincingly and deserved the extremely enthusiastic ovation that blossomed instantaneously.

Mr. Orth restored my faith in the ability of keyboardists to present this Brahmsian bear in a live recital setting, without the recording engineer smoothing over any unpleasantness. After my previous two experiences, I was beginning to think that it was just a bit too much for a lone interpreter to Handel.

At this juncture, many pianists would have needed to lie down for a while, but Mr. Orth instead plunged into a solid and meaningful set of Chopin. His “Polonaise Fantaisie” was a well-paced narrative, this artist perfectly content with a relaxed, ruminative tempo throughout. The Grand Waltz in A flat was correctly an impressionistic concert version rather than a dance. Mr. Orth’s Chopin is more cerebral than visceral, and ultimately interpretively rewarding.

The Nocturnes in E major Op. 62, No. 2 may not be whistled much on the streets outside of Warsaw, but Mr. Orth made a strong case for its circuitous storytelling. Finally, the Scherzo in the same key (Op. 54, No. 4) was charmingly offered with a lightly urbane touch. “Iberia” by Isaac Albeniz rounded out the program.

***

Erich Kleiber was once asked to direct a production of “Der Rosenkavalier,” but he insisted on three full-length rehearsals of the orchestra. The theater manager, trying to counter such an expensive measure, assured the maestro that the musicians already knew the score quite well. “In that case,” Kleiber quipped, “I shall need six rehearsals.”

Kleiber, whose son Carlos was also a prominent conductor, led the world premiere of Berg’s “Wozzeck” and died on January 27, 1956, the 200th birthday of Mozart. Kleiber was also one of the first Europeans to recognize the genius of the Mexican composer Silvestre Revueltas, fashioning a concert suite from his music to the 1935 Fred Zinnemann film “Redes” (“Fishing Nets”).

This suite was featured by the Philharmonic Orchestra of the Americas Thursday night at Alice Tully Hall. It proved well beyond the reach of the ensemble.

The Kleiber-Revueltas suite relies on subtle changes of instrumental color and timbre and rather dramatic surges of sea-inspired storm clouds. For a frame of reference, think of the roughly contemporaneous “Four Sea” Interludes of Benjamin Britten. But the best this group could offer was a mechanical approximation of the notes.

Although it is tempting to call the group a youth orchestra, most of the players are in their late 20s, although one violist who has to be pushing 60 (his mother must be really proud). As a unit, they are several steps below the average ensemble from the Manhattan or Juilliard schools, but they did exhibit a good deal of commitment and concentration. There is undoubtedly quite a bit of individual talent in those chairs; the responsibility for their waywardness and phlegmatic delivery appears to rest rather squarely on the shoulders of their conductor, Alondra de la Parra.

Ms. de la Parra employs extremely wooden gestures, never straying from the most elementary of beat patterns. This begs the question of whether she feels the need to be remedial because her charges are inexperienced or whether her players are uninspired because of her pedestrian leadership style. Either way, it was a bumpy night.

Mozart Camargo Guarnieri (great name, huh?) was a Brazilian composer who studied in Paris. He wrote “Encantamento” in 1941, and it proved to be an interesting series of mood pieces. The group struggled with the coloristic passages and the chiaroscuro overlay, but overall acquitted itself respectably. I got the distinct feeling, however, that we were only hearing the penumbra of the work.

The 20-year-old Venezuelan bassist Edicson Ruiz appeared as a soloist in the world premiere of the Double Bass Concerto of Paul Desenne. Mr. Ruiz was attached by electronic cord to some sort of device that I would have assumed was an amplifier, except that his seemingly dexterous playing was virtually inaudible throughout. The piece was a typical contemporary hotchpotch, with arbitrary notes and passages strung together in cynically random ways.

Those who disparage Astor Piazzolla as a composer might want to hear one of his essays immediately after an effort by Mr. Desenne. His “Tangazo” is quite beautiful, and was made more palatable on this evening by its almost total reliance on the string section. Mr. Piazzolla employed the rhythms of the dance in a subtle, flowing, circadian style, as opposed to Mr. Desenne and his gratuitous usage of percussion instruments. But Ms. de la Parra never really let her musicians go; they were always encased in that foursquare prison of hers.

A very disappointing evening.