Plácido Domingo was born in a trunk, so to speak. His parents ran a zarzuela company — and zarzuela, as you know, is popular Spanish opera, or operetta. Mr. Domingo has been spreading this music around the world. And he performed a concert of it at the Salzburg Festival on Thursday night.

He was supposed to share the concert with Rolando Villazón, the young Mexican tenor who is something of a protégé of his. But Mr. Domingo was the only tenor on the stage of the Great Festival Hall. Mr. Villazón had to cancel, owing to vocal fatigue (or some such). In his place was a soprano, also a protégée: Ana María Martínez, Puerto Rican born and New York raised. Everything worked out happily.

The concert opened with the overture to “El bateo,” by Federico Chueca. The piece is frothy and fun — sort of Spanish Johann Strauss, Jr. Jesús López-Cobos was on the podium, and his orchestra was not exactly a Spanish one: the Mozarteum Orchestra, Salzburg’s own. But they played Spanishly enough, catching the conductor’s wonderful spirit. Don’t let me condescend to the Chueca piece: Mr. López-Cobos and his charges generated real excitement with it.

Then Mr. Domingo came out for his first number — and he looked like a million bucks. He sang that way, too. For about 10 years now — 15? — I have referred to him as “the ageless Spaniard,” and that description still applies. Yes, he was miked, but he was in fine shape, and sang essentially the way he always has. I don’t need to tell you how that is. His voice and style are maybe more familiar than your own.

Following Mr. Domingo was Ms. Martínez, whose first number was “De España vengo.” This is the chestnut that the late Victoria de los Angeles used to sing (irresistibly). Ms. Martínez is very poised, well trained, and mature. Her sound is a little bit contained — a little un-vibrant — for zarzuela. Being born into a language is no guarantee of anything. But Ms. Martínez has many compensations, among them a dignified charm. Is it possible for charm to be dignified? I believe so, and Ana María Martínez embodies this quality.

On it went, through the night: arias, duets, orchestral pieces. The composers included Federico Moreno Torroba, Jerónimo Giménez Bellido, and José Serrano (not to be confused with Castro’s friend who represents the Bronx in Congress). In all likelihood, there were very few Spanish speakers in the audience, and there were no supertitles or texts. And yet the singers’ messages seemed clear enough: “el amor,” your achin’ “corazón,” etc.

Mr. Domingo went all out, yet he did not strain himself — this is a savvy pro. The songs were low enough to suit his baritonal, elegant tenor. He floated one little A in a head voice — that was really sweet. And he did not have a single troublesome moment. Once, when Ms. Martínez was singing an aria, he contributed some high-class humming, in counterpoint.

As for the soprano, she never lost her poise, never lost her charm, and never ceased to be winning. When the evening was over, a famous singer in the hall said in a private conversation — which is important — “She sang perfectly. Perfectly.” And it was true. One might have wished for a tad more color, or abandon, here and there. (Ms. Martínez is a fine Mozart singer, by the way.) But she didn’t put a foot wrong.

The conductor, Mr. López-Cobos, was fully engaged all through. He is a skillful accompanist of singers, among other things. Not too deferential, not too imposing — just smart.

One of the orchestral pieces was the Ritual Fire Dance from Falla’s “Amor brujo.” This was a little bit dainty and bloodless, I believe — a little French. But Mr. López-Cobos must be granted his view of Falla. And, at the piano, the excellent young Bradley Moore did something of an Alicia de Larrocha act.

You should have seen, later in the concert, two Germanic percussionists jammin’ on Latin instruments. Priceless.

It will not be hard to guess how the encores went: First, Mr. Domingo sang a number, and it was maybe his best singing of the night. He brought the capacity crowd to its feet. Then Ms. Martínez sang a number, and you know? It was probably her best singing of the night, too. They finished off with a duet.

But the evening was not quite over: Local officials gave Mr. Domingo the key to the city, or the equivalent. One of them commented that Mr. Domingo had sung about 50 performances in Salzburg. In his own remarks, Mr. Domingo reflected that he wished it had been 100. The backstory is: A former administrator did not invite him. But it was not a night for bitterness. It was as festive as nights get in Salzburg.

I keep calling Mr. Domingo “the ageless Spaniard,” but his repertoire is doubtless contracting. He is managing his career phenomenally well. And of zarzuela, he remains the undisputed master. His parents would have hugely enjoyed last Thursday night.