The Chicago Symphony Orchestra hosted guest conductor Michael Tilson Thomas and pianist Jeremy Denk this weekend in works of Mahler, Beethoven and Brahms that felt familiar yet oddly fresh (or bizarre, depending on one’s point of view). The program comprised Mahler’s Blumine, a freestanding work originally used as the second movement of his First Symphony; Beethoven’s Piano Concerto No. 3 in C minor; and the Piano Quartet in G minor of Brahms, in the 1937 orchestral arrangement by Arnold Schoenberg.

Blumine is relatively unknown, and one had the strange experience of hearing a work so clearly in Mahler’s style, the details of which were yet unfamiliar. Principal trumpet Christopher Martin delivered a ravishing yet understated opening solo. When performed individually (as opposed to within the First Symphony), Blumine features no other trumpets, and no trombones or tubas, and there was a coincidental but quintessentially Mahlerian poignancy to Mr. Martin’s physical isolation far upstage when playing this solo. Maestro Tilson Thomas’ conducting was dignified and magnificent, as was the case the remainder of the evening.

With more familiar repertoire came no greater predictability. Mr. Denk’s take on the Beethoven was unique to say the least – his rhythmic treatment of the work was far freer than most other pianists’, for better or worse, and there seemed a constant desire to add surprises and thwart the listener’s expectations. Mr. Tilson Thomas began the Allegro con brio with a brisk tempo and brooding anticipation of the pathos to come. Mr. Denk made a strong initial statement but soon parted interpretive ways with Mr. Tilson Thomas. When not overshadowed by his own wild physical gestures, Mr. Denk played with a romanticism that tended to avoid directness of phrasing, and inflected lyrical passages with an excessive degree of rubato. But to each his own – there’s certainly nothing wrong with an interpretation that seeks to enliven an old and often boringly-rendered favorite, as long as the playing is sincere. Still, one wonders if Beethoven’s music truly needs this kind of shock value to be meaningful and relevant.

Most jarring (and enjoyable) was the CSO’s performance of Schoenberg’s orchestration of the Brahms quartet. Schoenberg declared, in a letter to music critic Alfred Frankenstein, an intention “to remain strictly in the style of Brahms and not go farther than he himself would have gone if he lived today.” Schoenberg doesn’t add notes, change rhythms, or anything else not original to Brahms’ score, but he does flesh it out to a full orchestra, including several instruments that Brahms never used. In addition to creating new timbres, Schoenberg uses the orchestra to “interpret” phrasing, varying the instrumentation in repeated material to replace the more subtle shadings required of a chamber ensemble. At times his use of the orchestra does feel like a completely natural extrapolation of Brahms; the oboe gives a lovely color to the snaking melody that opens the second movement, and percussion is ingeniously used for playful mock-grandeur in the animato of this movement as well as in the final Rondo alla zingarese. Schoenberg’s reverence for Brahms cannot be overstated (his essay “Brahms the Progressive” is one instance of his devout advocacy for the master), but it is hard not to take some moments in this orchestration with a grain of salt. The xylophone at times makes the music sound a bit too much like parts of Saint-Saëns’ Carnival of the Animals, an aesthetic I highly doubt Brahms aimed for. And the dark first movement changes colors in a way that seems more a demonstration of Schoenberg’s imagination than an illustration of Brahms’ emotional ideas. Indeed, throughout much of this piece Schoenberg reminds one of a child who, excited at the acquisition of a 96-count box of crayons and eager to display his virtuosity, lacks the discretion to restrain himself in using them all in mind-numbingly quick succession.

Whatever quirks the piece does have, it was given a heartfelt and mature reading tonight. Mr. Tilson Thomas was in complete expressive and coloristic command, and the musicians of the CSO were stunning. Schoenberg’s sadistic assignment of sixteenth-note passages in the finale to the trombone section was met with aplomb, as were wind and string solos.

Perhaps the most touching moment of music in this last work, and maybe even the whole concert, was a passage in the fourth movement which Schoenberg, before building up to a big finish, leaves exactly as it is in the quartet – a brief exchange between the solo violin, viola and cello. It was an act of utmost deference to Brahms, and a reminder that bigger, bolder, newer, or more “interesting” does not necessarily mean better.