Maxim Vengerov was to play two Mozart concertos on Thursday night, and he was also to play in Mozart’s “Sinfonia concertante.” In the end, he did only one concerto. I will explain in a moment.

The formidable Russian violinist was in Carnegie Hall, joining up with the UBS Verbier Festival Chamber Orchestra. He “play-conducted” — that is, he served as both soloist and conductor, as so many musicians do these days.

The Verbier Festival is a Swiss affair, and the Chamber Orchestra is made up of young professionals from all over. Like golf tournaments and baseball stadiums, they have a corporate sponsor: UBS.

Mr. Vengerov and this group began with Mozart’s Concerto No. 2 in D, K. 211. The world knows that Mr. Vengerov is a virtuoso, even a super-virtuoso. He can tear through the hardest, thickest music like nothing. But can he play Mozart? The cliché has it that Mozart is the ultimate test for any musician: instrumentalist, singer, or conductor. The cliché is right.

And of course Mr. Vengerov can play Mozart, being a complete musician. In K. 211, he was fairly free, but not un-Mozartean. He was individual, but well within bounds. He was playful and personable, but then, so was Mozart, not only in his composing, but also in his violin playing, we understand. Mr. Vengerov showed some flash in his cadenza — in fact, he went to town. But he did nothing stupid.

As for his conducting, he seemed to enjoy that responsibility, very much. Then again, he seems to enjoy everything — life itself — very much. The orchestra played with an attractive, darkish sound, and they were unified and engaged at every turn.

After this opening Mozart, Mr. Vengerov conducted Shostakovich’s Chamber Symphony, Op. 110a, which is really his String Quartet No. 8, transcribed by Rudolf Barshai (a venerable Russian violist and conductor). The quartet is a great piece, of course — one of Shostakovich’s best — and Mr. Barshai’s transcription absolutely works.

Also absolutely working was Maxim Vengerov, who led a superb account. He showed that he understands every bar of this music, and the work as a whole. He was able to impart this understanding to his charges, who, presumably, now have it. The Chamber Symphony was severe, ominous, frightened; soulful, inspiriting, lush — everything Shostakovich calls for. Mr. Vengerov and the orchestra demonstrated tension within beauty, or beauty within tension. And this account, overall, was very, very Soviet, if you know what I mean.

You can hear this work played by more established ensembles, and conducted by more established conductors. You would be hardpressed to hear it better.

Before the second half of the concert began, Mr. Vengerov had an announcement to make: He had injured himself somehow, and was taking his playing day by day. On this evening, he had had enough. He would not play the violin part in the “Sinfonia concertante,” and he would not play Mozart’s Concerto No. 4, as previously scheduled. But he had other music up his sleeve.

Replacing him in the “Sinfonia concertante” was Mayumi Seiler, a violinist born in Osaka, raised in Salzburg. (How ’bout that?) The other soloist in this work was the violist Lawrence Power, a Brit. Ms. Seiler played tastefully and pleasingly, if a little demurely. Mr. Power played more zestfully — Powerfully, if you will forgive me! — but not overly so. And he exhibited a beautiful, rich, and satisfying viola sound.

Unencumbered by violin duties, Mr. Vengerov concentrated fully on conducting, and was top-notch. The beginning of the piece was sweeping and exciting. And the piece at large was both free and correct. With his baton, Mr. Vengerov showed a wonderful sense of phrasing, of breathing, just as in his playing.

And he ended his rearranged program with a symphony: Mozart’s Symphony No. 29 in A, K. 201. By this time, we could expect spiffy conducting, and that’s what we got. The UBS Verbier Festival Chamber Orchestra played clearly, stylishly, and beautifully. Mr. Vengerov has a special way with rhythm, and he had the orchestra share in it. He had the orchestra share in his musicality generally.

This requires strong leadership, a kind of alchemy. I regard Mr. Vengerov as an honorable pied piper, delighting in music, bringing others along with him.

The day after this concert, I mentioned to a friend that Mr. Vengerov had proven an excellent conductor. I guess my tone was surprised. She said, “Why are you surprised? He’s a fabulous musician.” True.