Of all the classics in ballet it is "Don Quixote" that most resembles an operetta, or zarzuela if you will. Last night at the Kennedy Center, in the first of five weekend performances of the piece, the stage was abubble. Ludwig Minkus' music is not the reason. It may be lightweight, technically unproblematic, predictably lilting, with a scant melodic elegance to recommend it, but that is equally true of this composer's "La Bayadere" or "Paquita."

The choreography, originally by Marius Petipa with input by a dozen others, is solidly academic despite its Spanish gloss. True, the story (with its bare similarity to the Cervantes) is funny, but then so is that of "Coppelia," which seems the equivalent of a comic opera. It is the characters and their moral tone that give "Don Q" its style. Not one of them is better than the people on the other side of the footlights.

Crucial for a vivid performance of "Don Quixote" is this sense of the real. Though the protagonists are drawn in broad strokes, neither the beautiful Kitri nor her lovers are purely one thing. The American Ballet Theatre cast projected the characters' strengths and collapses with a high sense of fun.

Martine van Hamel, as Kitri, has learned to dally. She used to glide too seamlessly through those bravura variations. Now she slices movement sharply, stabs the floor with her pointes and turns her broad jump into a wicked back kick. It was a luscious impersonation by the ample ballerina. And, she was partnered superbly by Patrick Bissell as her sort-of true love. He held her high above his head, caught her easily when she came hurtling at him, and he managed it all while keeping in character. Bissell's dancing, though, was not his best. It was strong and broad but sometimes lacked control because of unstretched, unpliant legwork.

Ross Stretton was aptly sharp and fleet as the matador. Nevertheless, more pliancy of torso and a bit of Bissell's breadth would not detract from the role. Others in the big cast that poured tumultuously onto the stage caught the eye. Susan Jaffe with her sensual extensions and quicksilver Cheryl Yeager provided just the right contrast to van Hamel's grandiose balances in the dream scene. Victor Barbee managed to suggest that Kitri's rich suitor is a fop because he is so precise. Placed in the finale between Gregory Osborne and Robert La Fosse, two of the company's most promising technicians, Barbee had no reason to be ashamed of his dancing either. Johan Renvall, as the urchin who mimics the matador, made the air seem his element.

Given its champagne nature, "Don Quixote" should have been scheduled for New Year's weekend rather than just before Christmas. If one has reservations about Mikhail Baryshnikov's staging, it is that he sometimes fails to focus the action core on that bubbling stage. Alan Barker conducted competently.