The higher possibilities of opera as music drama are so varied that we are often satisfied when only a few of them are realized. Once in a rare while, however, there comes the coincidence of a composer's genius with that of his interpreters, a moment when intelligence, craft and inspiration conspire to create the kind of music theater that is seldom experienced and never forgotten. The New York City Opera's new production of "Don Giovanni" made Thursday night at Wolf Trap one such moment.

Justino Diaz was born to sing Mozart's complex hero, and our generation is fortunate to have him.His Giovanni communicated instantly the cruel urgency of fading youth, the jaded frustration of a decadent age. He made sense of the paradoxical human attraction for the repulsive, his rich bass voice sometimes at odds with his slender, sensuous presence. With nature and the muses very much on his side, Diaz owned the stage. Countless details of this treacherous role, from the big arias to the simple recitatives like ". . . cara la mia Zerlina," were thought out to the point of spontaneous, genial effect. And when Don Giovanni waited alone on stage for pleasures that would never come, while singing "Deh vieni alla finestra," we came closer to understanding the genius of Mozart and DaPonte and the frailty of being human.

The Donna Anna of Carol Vaness displayed the struggle of purity and passion. A true spinto voice gave us a woman full of anger, anguish and a touch of guilt. Vocally she held back nothing, her fragile and delicate top B flats and her reckless runs in "Non mi dir" thrilling us with abandon.

Thanks to faith Esham's playful and gorgeously sung Zerlina, there was an air of hypnotic seduction in the famoud duet "La ci darem la mano." Diaz toned down his voice and matched the fiery peasant's every nuance in one of the most expicitly sexual stagings this scene has enjoyed. The seduction of course was interrupted by Donna Elvira, played by Esther Hinds. Hinds' soprano is too small to be so veiled in the middle, with an odd edge at the top of the scale and an incipient vibrato below an A when sung from the chest. She alone in this festival cast sported bland deportment and resorted to stock gestures. This was an Elvira who appeared more bored than outraged at Leporello's cataloguing of his master's exploits, although her singing was quite impressive in the ensembles.

Carlos Chausson as Leporello, for his part, sang with morbid pleasure, a servant at once proud of his master and ripe for revolt. As Don Ottavio, Joseph Evans was the picture of blond innocence; in spite of a hint of misplaced portamento, his was a gem of a vocal and dramatic portrayal. A defensible but wrong decision to cut the Zerlina-Leporello duet, "Per queste manine," along with all the music between Ottavio's "II mio tesoro" and Elvira's "Mi tradi" only made the lady's rage petty by comparison with the depths of the devotion sung by Evans.

There were a few inevitable problems associated with touring. The smoke at the end was more audible than visible. Unforgivably, a nervous stagehand made a surprise cameo appearance during Donna Anna's "Crudele" dramatic recitative. But nothing could hold back John Cox's brilliant direction. Julius Rudel was self-effacing at the podium and frugal at the harpsichord. The chorus was far stronger than on the previous night's "Barber of Seville." And the solid sets and suggestive costumes by Michael Annals make this production one of NYCO's finest. It is hard to imagine a finer "Don Giovanni" anywhere. The repeat is tommorrow night.