Attentive readers of this newspaper may remember a piece published in early January. In it, I glanced at the rest of the classical-music season, suggesting some highlights. I said that, if there was one experience not to miss, it was James Levine’s “Fidelio,” at the Metropolitan Opera. If you could spend your money on only one thing – spend it on that.

Well, Beethoven’s opera had its season premiere at the Met on Monday night – and Mr. Levine wasn’t there. As you may have heard, he took a tumble onstage in Boston earlier this month. He will be out for the rest of the season, nursing a shoulder.

Mr. Levine is the best “Fidelio” conductor in the world, so it wouldn’t be sporting to measure anyone else against him. The Met had a substitute – Paul Nadler – who was respectable. Mr. Nadler has conducted in this house many times. He is music director of the Southwest Florida Symphony Orchestra, and works regularly elsewhere as well.

He did not begin happily on Monday night – that is, Beethoven’s overture was poor. It lacked authority and vitality, and the orchestra was ragged. Then, when the curtain went up, that orchestra covered the soprano and tenor (Marzelline and Jaquino) who were singing onstage.

I will not dwell on Mr. Nadler’s failings, but will instead mention something admirable: The music surrounding the grave-digging in Act II had superb tension – indeed, a rare tension. And the orchestra had played with wondrous warmth at the beginning of Act I’s quartet.

One must cite an individual – the oboist, who acts as Beethoven’s angel. He, or she, did the job.

Also doing the job was the soprano in the title role, Karita Mattila. She and Deborah Voigt have been sharing this role at the Met for the last several seasons, and they both excel in it. Ms. Mattila was in top form on Monday night, singing with ease and power (power both vocal and dramatic). You could pick at some things she did, but they would be merely that: picks.

Opposite her as Florestan was the tenor Richard Margison. The Met has had, in recent seasons, Ben Heppner and Johan Botha. Those tenors are perhaps more celebrated than Mr. Margison, but he was at least as good. He began Florestan’s music – “Gott! Welch Dunkel hier!” – with unusual quietness. The cry of “Gott” was no cry at all, but rather a whisper. It certainly had no exclamation point. But this was an arresting choice, and Mr. Margison shaped the rest of his music well, too. He did virtually no barking or straining, in a punishing role (brief as it is).

Rocco, the jailer, was Kristinn Sigmundsson, the Icelandic bass heard earlier this season in the Met’s “Romeo et Juliette” (Gounod). He sang solidly and intelligently, often with an apt paternal tenderness. The baritone Alan Held – who had been Wozzeck here a few months before – made a super-sinister Pizarro. He filled you with revulsion, which was right.

And that duo from the beginning of the opera, Marzelline and Jaquino? Those parts were taken by Jennifer Welch-Babidge and Gregory Turay. She was, as usual, bright, forward, and chipper. She can really release her upper register, letting the notes fly, in the manner of Dawn Upshaw. And Mr. Turay showed off his sweet, lyrical tenor.

Another impressive tenor was that of Russell Thomas, who sang the lines – the transcendent lines, by the way – of the First Prisoner. He used what you might call a melting trumpet.

Saving the day at the end of the story was Fernando, in the person of James Morris, the veteran bass. His singing was full of generosity – but, no matter what the role, or song, I always sort of hear his Scarpia (the villain from “Tosca”). Perhaps you have this experience as well.

A “Fidelio” depends on the chorus, and the Met’s handled its music admirably. This was especially true of “O welche Lust,” as the prisoners emerge into the light. The production is the smart and suitable one of Jurgen Flimm, which debuted in 2000. (Mr. Flimm is now chief of the Salzburg Festival.)

Those disappointed by Mr. Levine’s absence are far from wrong, even if they realize the show must go on. I wish to share a memory: of Mr. Levine conducting the final chorus, years ago. His face is upturned, he is singing along. You’ve never witnessed such joy in music-making.

And what joy this opera contains! “Fidelio” is, among other things, one of the greatest tributes to marital love in art. Interesting that Beethoven, who never married, should have known so well what true marriage is. His opera is also one of the greatest tributes to political freedom in art. “Fidelio” stands for decency, for moral reason – for good.

And Beethoven never worked so hard on anything in his life. No composition cost him so much, no composition involved so much sweat: so much rewriting, rethinking, struggle. By God, it was worth it.

A couple of footnotes, if I may: The Met’s performance on Monday night was dedicated to the late James King, a prominent Florestan. And, before the performance began, the Met’s “seatback titles” informed us that the production had been paid for by Alberto Vilar. One of the great arts philanthropists of our time, Mr. Vilar fell from grace – losing his money and his reputation. I hope, and actually expect, that, like the characters in “Fidelio,” he will find his way back into the light.

“Fidelio” will be performed again on March 24 & 28, and April 1, 4, 8 & 13 at the Metropolitan Opera House (Lincoln Center, 212-362-6000).