The Metropolitan Opera brought its first week in the Kennedy Center to a strong close on Saturday with Mozart's "Don Giovanni" in the afternoon and "Cavalleria Rusticana" and "Pagliacci" in the evening.

It was wonderful to see "Don Giovanni" in the glorious production devised by Herbert Graf with sets and costumes by Eugene Berman. Elegantly refurbished, this, which is one of the Met's handsomest properties, gives a new generation a glimpse of former glory.

James Levine conducted a performance that balanced Mozart's most powerful drama with some of his most achingly beautiful lyric writing. On the whole he was fortunate in a cast headed by Sherrill Milnes, who calls on a beautifully focused lyric sound to match his vivid appearance. One of the welcome effects of the lightened texture of Milnes' rich voice is the ensuing balance between Donald Gramm's deeper bass as Leporello and the black sound of John Macurdy as the Commendatore, the kind of layered impression Mozart desired.

Milnes' mixture of voice and stage presence makes his heralded successes at seduction wholly believable. He handles the wide range of scenes with a vocalism that gleams like the champagne he tosses off, darkening at will, as when he suggests Donna Elvira's madness.

Paralleling Milnes' art is Gramm's limitless skill and peerless singing. He continued the triumph of his Catalog Aria throughout the opera as he played off each of the other characters. The sheer beauty of his voice remained constant whether in arias or while displaying his command of Mozartean patter. Nowhere was the Gramm-Milnes team more brilliant than in their exchange of costumes and personalities.

Johanna Meier and Carol Neblett offered much that is needed in Donna Anna and Donna Elvira, though neither was completely at ease in the most agile passages. Both looked ideal in the long roles and handled the ensemble scenes with considerable beauty.

Kathleen Battle's Zerlina was pert and lovely in sound, full of the right touches of indignation at the Don's attempts and sympathy for her bruised Masetto. In the latter role, Lenus Carlson sang and acted with unchanging conviction and beautiful voice.

John Macurdy made the Commendatore's role believable in the opening scene and thrilling in the final trio. David Rendall sang Don Ottavio with good musicianship and remarkable phrasing. His voice, however, is not the instrument needed for the role and his stage movements tend to be awkward.

One of the joys of the Berman sets is the way the stage is used for the banquet scenes. In the first, the three stage bands were a delight to see and hear. The final scene, however, was marred by the fact that, probably for reasons of touring, it was not possible for Don Giovanni to disappear properly. Milnes had no recourse but to walk offstage in an unconvincing manner. And even on tour there should be some way of making sure that solid walls and buildings do not wave quite so freely.

Saturday evening was all blood and guts. While "Pagliacci" is based on a historical incident, it comes across no more strongly than the slice of Sicilian life depicted in "Cavalleria Rusticana."

Each opera profited immensely from the production, sets and costumes of Franco Zeffirelli. Rarely has either seemed more honestly depicted in background and crowd actions. David Stivender, conducting both operas, gave every possible nuance, while keeping the basic tensions dominant. As the Met's distinguished choral master, he made the most of the big chorus episodes.

One of the strongest stage portraits seen in the Met's week is Mignon Dunn's Santuzza. Turning her beautiful mezzo into a powerful dramatic soprano, she brought every aspect of the tragic role into brilliant focus through the finest kind of stagecraft. From a harried, tortured entrance to her desperate, horror-filled final shock, Dunn, by every movement of hands, of walk and stance made clear the motivation behind every note she sang. And her singing was a thing of power and beauty.

Two men sang handsomely in both operas. Cornell MacNeil's Alfio was a model portrait, almost Mafioso in its tight-lipped drive for revenge. His singing, once past the troublesome "Il cavallo scalpito," met every demand. The man who sings both Alfio and Tonio spends a certain amount of time handling a whip in each role. Alfio's whip offered a little more than a feeble whisper where it should have snapped, while Tonio's was strangely ineffectual. But in the latter role, from the moment he began the Prologue, the veteran baritone seemed to have found the fountain of youth. He acted with cunning and sang, top A flat and all, with easy beauty.

Ermanno Mauro was the other singer doing double duty Saturday night, singing eloquently as Turiddu and even more so as Canio. There was a minor contretemps in the opening offstage serenade in "Cavalleria," when the harp took the wrong turn in the road, but things were quickly righted. Artistic point: With MacNeil providing an unusually strong Tonio, even to the extent of putting a fatal dagger in Canio's hand, it would have been better to revert o Leoncavallo's clear direction and have Tonio sing the famous final line, "La commedia e finita," rather than having it spoken by Canio.

Geraldine Decker's Mamma Lucia was unusually effective and Isola Jones' Lola as provocatively seductive as she was supposed to be.

Patricia Craig sang a lovely Nedda, shading the role effectively and, in the duet with Silvio, reaching some exquisite moments.She could be more careful of those trilled leaps in the Bird Song. Her Silvio was one of the Met's finest younger artists, Allan Monk, the beauty of whose singing cannot be overpraised. Philip Creech sang and acted Beppe with fluent ease. Puzzlement: Where, on that almost barren stage, were the birds Nedda sang about so glowingly? In that one dismal tree no self-respecting bird would look at twice?