[…] The music director laureate of the San Francisco Symphony has been undertaking a kind of farewell tour with some of the orchestras that have meant the most to him. And so it was that he valiantly arrived Monday in Chicago for a series of rehearsals and then took the stage Thursday evening looking a bit frail but also determined and strong.

Tilson Thomas first conducted the CSO at the Ravinia Festival in 1970, and he has appeared with the ensemble on about 40 other occasions at Ravinia and in Orchestra Hall, even leading an Australian tour in 1988. It’s an extraordinary history that got another important chapter Thursday evening.

After he slowly made his way to the podium amid warm applause, he turned to the audience and put the tip of his baton to his forehead and flipped it outward in salute.

What quickly became clear is that no allowances had to be made for the circumstances. Tilson Thomas was here to work, and that’s what he did, delivering a performance that will stand up to any in this hall this season.

The evening’s crowning offering was Arnold Schoenberg’s brilliant 1937 orchestral transcription of Johannes Brahms’ Piano Quartet No 1 in G minor, Op. 25, an amalgamation of these two giant talents but very much in keeping with Brahms’ original intent.

Tilson Thomas oversaw an interpretation throbbing with energy and immediacy — the orchestra right with him as he deftly responded to the work’s ever-changing moods and feels and brought a clear-eyed clarity to the whole.

He adroitly handled the multiple themes of the work’s long, complex first movement, drawing beautiful, ideally balanced playing from the brass in its agitated, fanfare-like moments in the spotlight.

The piece ended with a wonderfully spirited take on the galloping fourth movement, nicknamed “Gypsy Rondo,” with Tilson Thomas bringing perfectly calibrated tempos and breezing through the changing rhythms and meters with ease.

Making the performance even more impressive was the conductor led it all by memory. He had the score in front of him but never consulted it. He flipped through the pages after the first movement to re-establish his place and didn’t bother after that.

The big revelation of this concert was the concert’s opener, Wolfgang Mozart’s Six German Dances, K. 509, which, amazingly, the CSO had never performed before. Debuted in Prague in 1787, this 12-minute set of short dances is a light, jocular piece with plentiful doses of Mozartean charm.

Tilson Thomas clearly has an affection for this little gem, bringing to it discipline, yes, but also simplicity, airiness and, perhaps most important, a sense of fun. Adding to the work’s delight is a series of flitting piccolo solos handled with aplomb by Jennifer Gunn, whom Tilson Thomas rightly granted an individual bow.

What most of us want when it comes to death is to go out on our terms, and that is exactly what Tilson Thomas is doing: still making superb music and following his passion.

For a little more than two hours, he transcended the bounds of mortal earth and took a roomful of grateful listeners with him.