This week at the Chicago Symphony marked the second of two programs of Mozart and Beethoven, both of which were comprised of two symphonies framing a concerto. Originally slated to conduct both weeks, Christoph von Dohnányi was delayed in his arrival to Chicago for health reasons, but was able to return this week in what was a rather impressive showing.

The concerto in question was Beethoven’s Piano Concerto no. 2 in B flat major, with remarkable young pianist Martin Helmchen making his CSO debut. Beethoven’s first two concertos can superficially sound like Mozart, but with the intensity of Helmchen’s playing and the dramatic sweep he brought to the first movement in particular, there was no mistaking this was the work of the latter composer. Helmchen freely displayed a wide dynamic range, and there was a wonderful spontaneity about his playing as he seemingly threw caution to the wind in what was nonetheless a virtuosic performance.

The slow movement showed a more subdued side, and indeed the depth he brought anticipated the profundity of the slow movements in Beethoven’s later concertos. The opening chords were impeccably voiced, leading to a melody with wisely considered embellishments. Later in the movement, the piano was given a wondrous rippling accompaniment over winds and pizzicato strings, and near the end, was distilled to a single note line the right hand – even in such minimalist textures, Helmchen had the audience hanging on every note. The sprightly finale gave the work a joyous close, Helmchen giving emphasis to the syncopated rhythms and dance-like gestures perhaps inspired by the polonaise. Easily the most auspicious CSO debut of the season, Helmchen received an enthusiastic reception, and responded in kind with a keenly judged Moment musicaux no. 3 of Schubert.

In the Mozart symphonies, Dohnányi opted to place the cellos and basses on the left, as well as electing for a larger than typical orchestra for Mozart, which served to elicit a richer tone without ever faltering into bombast. From the onset of the Symphony no. 25 in G minor, one was immediately struck by the searing intensity Dohnányi brought to this crowning product of Sturm und Drang. There was additionally a remarkable transparency, allowing one to hear all the inner voices in perfect balance. Michael Henoch’s notable oboe solo led to the lighter secondary subject which all but danced, although in the darkness of the work it was given in the minor during the recapitulation.

The second movement was treated as almost an operatic aria, and truly sang; in the minuet, the trio strikingly featured a band of winds and horns, temporarily entering the realm of the banal. The orchestration asks for four horns, the only time in his entire symphonic corpus Mozart would make such a demand. The finale returned to the drama of the opening and was a movement of sharp contrasts – at age 86, Dohnányi is clearly showing no signs of waning intensity.

The evening concluded with the incomparable Jupiter Symphony – although fitting as it may be, it should be remembered that the now ubiquitous sobriquet was only appended posthumously by the publisher. Although Mozart couldn’t have conceivably known this would be his final symphony, he couldn’t have ended on a higher note in this veritable summation of the symphonic tradition up to that point. The spacious first movement was grandiose and ceremonial, the cascading winds a particular highpoint in the texture, and a wonderfully buoyant theme launched the development.

The slow movement, in stark contrast to the effervescence of the previous, began with muted strings, its endlessly lyrical melodies and delicate refinement an embodiment of everything we know to be Mozartian. The minuet in this symphony is certainly one elevated above the prosaic although Dohnányi seemed to emphasize the rhythmic pulse of its origins in dance. There's some attractive writing for bassoons in this movement, William Buchman admirably stepping forward for principal Keith Buncke. The finale is a towering fugue, an intricate web of counterpoint spun from the simplest of four note themes. Even when the texture was at its densest, it was presented with crystal clear pellucidity and an unabated vigor, never becoming dry and academic. While some conductors have delved deeper into the profundity of this enigmatic work than Dohnányi managed to do, in terms of sheer beauty of sound and vitality of playing it was nevertheless a performance to remember.