It’s not often the Seattle Symphony welcomes a new music director—Saturday night’s gala concert marked only the fourth such occasion in the past half-century. While Ludovic Morlot was relatively unknown to the orchestra at his hiring in 2011, having conducted here just twice—a gamble that paid off with eight innovative seasons of music-making—the new guy, Thomas Dausgaard, is already a known quantity; his debut with the SSO was in March 2013 and he was named Principal Guest Conductor that autumn.

Still, all the excitement of a new chapter for the orchestra was in the air, with the promise of surprises and discoveries to come. Just as Morlot introduced Seattle to a lot of contemporary French music, Dausgaard, born in Copenhagen, opened his tenure with a work by one of his countrymen: Carl Nielsen’s fizzing overture to the comic opera Maskarade, from 1906, a whirlwind of a piece that made me hungry to hear the whole opera, which has been staged only a few times in America.

The guest soloist, Daniil Trifonov, made the evening especially memorable with one of the most arresting and fascinating piano performances I’ve heard in some time. His vehicle was the fourth concerto by Rachmaninoff, to which he brought an extraordinary sense of introspection—not only in the gentle slow movement, where you’d expect it, but also in the lyrical passages in the fast movements. Not out to impress or to dazzle, but to mesmerize, it felt as though he was playing for himself at 3 a.m., and he pulled us into his reverie; the sudden loud ending to the first movement was like snapping awake after a dream. (This aural impression was reinforced by a visual one; Trifonov hunches over the keyboard like few pianists since Glenn Gould, and consequently a curtain of hair blocks us from his view.) His virtuosity, like the unbelievable liquidity of a few upward scales (I have never heard a piano sound quite like that) was entirely in the service of painstaking subtlety rather than showing off. Trifonov’s finger-tangling encore, which I didn’t recognize, turns out to have been a transcription of the “Silver Bells” movement from Rachmaninoff’s choral symphony The Bells, based on Poe’s poem.

The main showpiece of the evening was Richard Strauss’ tone poem Also sprach Zarathustra. Its ultrafamiliar opening, used in 2001: A Space Odyssey, got an extra dose of grandeur and drama from Dausgaard’s comparatively broad tempo and acute attention to dynamic detail. He brought further moments of freshness and surprise to the rest of the half-hour work: a gripping mood of veiled mystery and vast distance in the “Of Science” section, a feverish sweep to “The Dance-Song.” The evening ended with a musical toast—another work from his homeland, the “Champagne Galop” by Danish light-music master Hans Christian Lumbye, with the final cork pop releasing a burst of confetti over the percussion section.