The Metropolitan Opera ended its week in Washington much better than it had begun. Tchaikovsky's "Eugene Onegin," Saturday night in the Kennedy Center Opera House, was in every way a production worthy of one of the world's great opera companies.

"Onegin" is seen less often than the tired and overexposed "Lohengrin" and "Rigoletto," productions that led off the week. It was presented in a solid if not particularly imaginative staging, with singers who were deeply involved in the music and the story. The overall concept of the production was coherent and compelling, and the singing was always good, often outstanding. A search for problems must finally settle on a few lighting miscues and momentary lapses of balance between voices and orchestra.

The opera's worst problem is language. Americans have long been accustomed to going to the opera and not understanding the words. But tradition prefers that the words not understood should be in Italian, French or German. Operas in Russian, Czech or English often run into resistance from a substantial part of the audience. In the case of "Eugene Onegin," this resistance has banished to the fringes of the standard repertoire an opera that might be as popular as "La Bohe me" or "La Traviata" if its text were in Italian.

"Eugene Onegin" is one of the supreme operatic embodiments of the romantic spirit -- highly inventive in the series of episodes that pass for its plot, and superbly musical in its soulful melodies, somber harmonies and rich orchestration. Above all, it should appeal to opera audiences because of its vivid treatment of four characters who are all romantic cliche's brought to three-dimensional life through the power of music and acting: Lenski, the young poet doomed by his own obscure yearnings and dark insecurities; Tatiana, the heroine who grows from shy, awkward adolescence into mature, self-possessed womanhood in the course of the opera; Onegin, the blase', Byronic cynic who lives in isolation from his fellow men because life offers him nothing but boredom; Olga, la belle dame sans merci, a beautiful, thoughtless woman whose idle flirtation has fatal consequences.

The interaction of these four characters is highlighted by some of opera's greatest moments: the letter scene, a superb outpouring of idealistic young love and one of the supreme tests of a soprano's art; a bleak duel scene preceded by one of the finest arias in the tenor repertoire; a superbly ironic final scene in which Onegin, who had rejected the adolescent Tatiana in Act 1, is rejected in turn by the mature, married Tatiana in Act 3.

The music is immediately recognizable as prime Tchaikovsky, from the wispy, sentiment-drenched opening notes of the prelude through Onegin's final cry of despair. Clearly, the composer has studied Italian opera (notably "La Traviata," which occupies much the same emotional and sociological milieu), but the melodic contours are intensely Russian -- most explicitly in the folk-based melodies given to the chorus in Act 1. Tchaikovsky the great ballet composer can be heard in the work of the operatic Tchaikovsky -- notably in the dances, from the two ballroom scenes, which have sustained a concert life of their own independent of the opera. They also function, in the opera, as more than an inserted bit of color. The bright, energetic mazurka of Act 2 (stylishly danced by the Met's corps de ballet) provides an ironic introduction and background to a scene of flirtation, lovers' quarrel and a final, bitter falling-out of old friends that ends in a hotheaded challenge to a duel.

The Met's production served opulently the diverse riches of "Eugene Onegin." The cast had no weaknesses, from the four leading roles down to the smallest parts. The casting of the superb Lili Chookasian in the small role of the nurse is an example of the kind of concentrated quality the Met can bring to a production when it chooses. So were Andrij Dobriansky as Zaretski and Paul Plishka as Gremin, who has only five minutes in the spotlight but five splendid minutes.

Still, the star of the opera was unquestionably Carol Vaness as Tatiana. Her greatest moment was, predictably, the letter scene, in which she held the stage alone for more than a quarter-hour, taking the audience through endless virtuoso variations on the theme of impulsive young love. Her voice was flexible, tonally rich and superbly controlled. Equally impressive was her portrayal of character -- a particularly tricky assignment in this role, which grows from adolescence to maturity during the second intermission.

David Rendall was an ideal Lenski, vocally and dramatically. Tchaikovsky lavishes on this role some of his finest melodies, while the libretto imposes on it acting demands of unusual variety and subtlety. Nicolai Gedda might have done it equally well a while ago; I can think of no tenor active today who might be better.

Although it is the title role, Onegin does not emerge fully until after Tchaikovsky has rashly killed his tenor in Act 2. Victor Braun played it well throughout and rose to striking intensity in the last act. Isola Jones gave her usual smooth, problem-free performance as Olga.

The chorus, promoted from peasantry to nobility between Acts 1 and 2, sang and acted convincingly in both roles. Conductor Thomas Fulton directed a finely integrated interpretation, and the orchestra responded with its usual polish to Tchaikovsky's excellent score.