Still, his concept has intriguing elements and is strongly complemented by the compelling, vulnerable performances he draws from a strong cast, especially the astonishing soprano Nina Stemme as Isolde. And on every step of this Wagnerian trip to the edge of night, the way was led by the conductor Simon Rattle, finally back at the Met after his momentous 2010 company debut in Debussy’s “Pelléas et Mélisande.”

Mr. Rattle’s performance of Wagner’s monumental score, some four hours of music, impressively balanced clarity and richness, coolness and intensity, intelligence and impetuosity. The composer’s harmonic language, which ventures into bold, radical chromaticism, came through in rich, full-bodied orchestral sound. Mr. Rattle also brought uncanny transparency to the contrapuntal lines that mingle continuously in the music. Climactic passages crested with sound, and dramatic episodes generated plenty of heat. Still, Mr. Rattle is not one for swelling, emotive passion. Rather, he goes for incisiveness and vehemence.

Last season, Ms. Stemme triumphed in the title role of Strauss’s “Elektra” when the Met presented Patrice Chéreau’s stunning production. Her Isolde is just as outstanding. Her voice has enormous carrying power without any forcing. Gleaming, focused top notes slice through the orchestra. As Isolde went through swings of thwarted fury, yearning and despair, Ms. Stemme altered the colorings of her sound, from steely rawness to melting warmth. And it is not often you hear a Wagnerian soprano who takes care to sing with rhythmic fidelity and crisp diction.

[ Ms. Stemme on taking on this role, her biggest Met Opera assignment yet ]

If Isolde is a summit for select dramatic sopranos, Tristan may be an even harder assignment for a heldentenor. This production is lucky to have Stuart Skelton, who gives an honorable and courageous performance. His muscular voice may lack some warmth and ping. But he sings with musical integrity and feeling. And he paced himself impressively during the long, arduous scene in Act III when Tristan, mortally wounded and delirious, back at his ancestral home in Brittany, awaits Isolde. Attended by his loyal servant Kurwenal (the solid bass-baritone Evgeny Nikitin), Tristan keeps thinking he sees Isolde’s ship on the horizon, only to be shattered with disappointment, until she finally arrives, too late.