The Mostly Mozart Festival Orchestra played on Friday night, and two composers were on the bill: Mozart and Webern. The festival, of course, posited al ink between those two composers. Of course, you can posit a link between any two composers: Monteverdi and Mantovani, Byrd and Birtwistle. Such positings are what makes programmers feel useful and happy.

Conducting the Festival Orchestra was its music director, Louis Langrée, and his guest soloist was Christiane Oelze, the German soprano. Both canny, well-schooled musicians, they made a good pair. (Like Mozart and Webern?)

The concert began with the overture to Mozart’s opera “Idomeneo.” This is not one of his most popular overtures – but it is a great one. From Mr. Langrée and the orchestra, it had a bad start — a not-together one. And some of the playing thereafter was ragged. But the overture was incisive and conveyed the right spirit. Mr. Langrée showed his sense of rhythm to be excellent. And the music had energy without being breathless or crazed.

As the orchestra was finishing the overture, Ms. Oelze walked onto the stage — to sing an aria from that opera: “Quando avran fine omai … Padre, germani, addio!” Her voice was smallish, but carrying. And she forced nothing. In fact, she is an extraordinarily relaxed, self-confident singer. And a very smart one. She phrased and intoned almost like a violinist (like Zino Francescatti, for example). She is not merely a singer, but a musician.

And don’t the smartest ones tend to make the best Mozarteans?

In all, Ms. Oelze gave us, in this aria, a tasteful tour de force — if you will accept such a notion. And Mr. Langrée handled his band extremely well. The orchestra was bouncy, in the “period” style, but not ridiculous.

Then it was Webern’s turn: Ms. Oelze sang his “Five Canons After Latin Texts,” Op. 16. These are difficult little pieces, with challenging intervals — leaps. And, perhaps above all, the pieces take precision. Ms. Oelze supplied it. There was some impurity of voice, but Ms. Oelze never lost her stride. Again, she was very relaxed and confident, in this really daunting music.

The orchestra then played Mozart’s Adagio and Fugue, K. 546 — a look-back to Bach. From Mr. Langrée et al., it was not clinical, but impassioned. At the same time, it was not purple. Very well done.

Then it was Webern again, and Ms. Oelze — singing the composer’s “Five Religious Songs,” Op. 15. Like the canons, these are not five easy pieces — at all. But Ms. Oelze made them seem so. She sang them with aplomb.

And what are they, these five queer “Religious Songs”? Are they studies or are they (real) music? It’s a little hard to tell. And what does the singer/narrator mean? For example, she sings, “I go with joy in myheart”—butyouwouldn’tknow it from the music.

It was good to have an opportunity to hear Mozart’s “Masonic Funeral Music,” K. 477 — the guy could write anything, instantly. And this is a wonderful work. It is sad, of course, being funeral music – but it becomes warm, ennobling, and uplifting.

The orchestra played none of the (several) closing chords together — nota one. But, somehow, itcould be overlooked.

Next on the program was one of Mozart’s best-loved concert arias, “Misera! Dove son? … Ah! non son io.” I would have had it conclude the first half, rather than the funereal music. But the festival had it after intermission, and, of course, Ms. Oelze did a good job with it. I will tell you something simple: She sang much of the aria like she was talking to you. And she sang the music as though unaware of how hard it is. This was another tasteful tour de force.

Did she do anything wrong? Yes — she is not much of a triller. Or at least she wasn’t on this occasion. But that is a triviality. Ms. Oelze is a woman who seems to get the most out of her voice and the most out of her ability.

The program ended with one of Mozart’s great D-major symphonies, No. 38, called the “Prague.” And the opening movement — Adagio and Allegro — was superb. Mr. Langrée was at his Mozartean best. The Adagio had grace and breadth, and great internal drama. What would “external drama” be? Well, superficial drama — the kind that a conductor would manufacture, or try to manufacture. That’s not the right kind of drama — certainly not with Mozart.

Mozart’s transition from the Adagio section to the Allegro is one of the neatest things in music. And, from Mr. Langrée and the orchestra, it was delightsome and exciting. So was the rest of this movement. And the music was very, very alive — the opposite of perfunctory or false.

Now and then, it would have been nice to have more and better sound from the orchestra. But Mr. Langrée was so commanding, you could hardly complain.

And the ensuing movement, the Andante, was just as good as the opening movement, in its own way. Mr. Langrée did not dawdle — he never does. But neither did he hurry. He took his time, letting the music have its full beauty and impact. It was not on “period” Rollerblades.

The Finale rather was, unfortunately. It was a bit breathless and mechanical. At its worst, you thought of a computer, spitting out data. When Mozart said “Presto,” he did not mean mad or unmusical. But, mainly, this movement stayed (relatively) sane. And the flutist did very well, keeping her musical composure within an awkward tempo. All told, this was another first class night at the Mostly Mozart Festival. And, during the first two movements of the “Prague,” I had the following thought: Given his gifts, Mr. Langrée needs a bigger job.