It took a bit of doing, but the Kennedy Center has lured the New York City Ballet back to the fold, and the immensely gratifying results were on view at the Opera House last night in an opening program featuring the Washington premiere of Jerome Robbins' "Gershwin Concerto" and a pair of strongly contrasting pieces by George Balanchine.

It was Balanchine, the company's chief choreographer and pasha-in-residence, who told the Center last year that his troupe wouldn't return until the Opera House stage floor was fixed, i.e., made more resilient and less injury-inducing. Well, the Center did exactly that, with the help of the NYCB's stage manager Ronald Bates, who designed a new kind of removable flooring for dance. The company, in turn, is now back here for a two-week stay, with a bundle of fresh repertory in tow.

What the opening night proved is that even a single year without the NYCB is one year too many. It might be going too far to say that the life of a ballet fanatic would be unlivable without the troupe, but there are times when one feels that way. We've been spoiled in Washington by the company's more or less consistent annual visits -- now that the floor problem is solved, let's hope the spoiling resumes without interruption.

When the curtain went up on the first few minutes of Balanchine's "Divertimento No. 15," the sight of the dancers, their bearing and their movement, was nothing short of electrifying. It's not a question of this being the "greatest" company; ballet, like the other arts, is too rich in diverse styles and values to be measuring itself by publicity yardsticks. The NYCB is, to be sure, among the handful of the world's consummate classical ballet troupes, by virtue of its size, character and excellence. But beyond this, it is one of a kind. The Balanchine repertory and the NYCB dancers, hand-picked and personally groomed by the master, have no equivalent. The meshing of Balanchine's Russian roots and cosmopolitan culture with the company's American speed, strength and athletic moxie has produced something literally incomparable.

Robbins' new Gershwin piece, for four principals (Maria Calegari, Darci Kistler, Christopher d'Amboise and Mel Tomlinson, last night) and an ensemble of 12, is a model of lucid choreographic design. Each of the principals has a separate cadre of supporting dancers. In the first movement, one of the men partners both women; in the second movement, the second man does the same; and in the finale, each principal dashes on stage for a whirlwind passage and yields to the next, before the full group assembles for the close. It's an abstract ballet that picks up on the score with fleeting allusions to '20s pop dance styles and jazzy embellishments, as well as with the Art Deco pattern in Santo Loquasto's backdrop.

Like the music, however, the choreography doesn't quite rise to the promise of its own effervescence -- after a while the exhilaration begins to seem manufactured and wearying. And Loquasto's color combinations for the corps can cause seasickness -- a sort of beet red for the women, and coppery orange for the men, against a blue drop. Among the saving graces were the first big, splendidly amorous pas de deux for Kistler and D'Amboise in the first movement, and the level of performance throughout. Kistler, recently promoted to company principal and still the current wunderkind, has lost none of her bright-eyed galvanism, but she's added considerable technical assurance since we saw her last.

The evening's choreographic highlight was Balanchine's opening "Divertimento No. 15," set to the Mozart opus of that title and created in 1956. The miracle of inner and outer concordance between music and dance here is as close to perfection as ballet is ever likely to come, and the resultant expressive depth is the ineluctable outcome. The piece is also a textbook of neo-classic dance logic, in its geometric symmetries and the natural flow of its step phraseology. The cast was superb -- d'Amboise and Sean Lavery, dancing in this work for the first time, were joined by Merrill Ashley, Calegari, Lourdes Lopez, Kyra Nichols, Stephanie Saland and Victor Castelli as the other principals.

"Stars and Stripes," that old Balanchine blockbuster to Souza marches, brought up the rear, in a performance brought to climactic brilliance especially in Daniel Duell's solo, the Peter Martins-Heather Watts duet and the buoyant precision of the ensemble as a whole. At first sight, "Stars," with its stage-filling gaudiness and Hollywood extravagance, looks like a cornball ballet, until you look closely at what a furious classical workout the dancers are getting, and note how those parade-ground formations echo the Petipa heritage that Balanchine has transcribed into Yankee terms. Incidentally, it was learned afterwards that Balanchine is in Washington, which means that his recently faltering health is on the upswing -- it's good to have him with us.