What is it about Haydn’s string quartets that we love so much? Is it the headlong rush of endorphins to the brain they provoke? Or the sense that the universe — despite all evidence — is a warm, well-ordered and fundamentally happy place? Who knows? Suffice it to say that Thursday night’s concert by Musicians from Marlboro at the Freer Gallery opened with a performance of Haydn’s String Quartet in A, Op. 55, No. 1 that was so fresh and full-blooded, so full of earthy vitality and sheer sensual pleasure, that it made you happy to be alive — even in election season.

Musicians from Marlboro is the touring ensemble of young professionals brought together at the venerable Marlboro Music Festival in southern Vermont every summer, and its members are among the best of the best young players in the country. This year’s crop includes the gifted violinist Soovin Kim, who — with the equally fine Benjamin Jaber on horn and Matan Porat at the piano — turned in an extraordinarily powerful reading of the Trio for Violin, Horn and Piano by Ligeti. It’s an homage of sorts to Brahms, and there is something Brahmsian in the golden, murmuring warmth of the opening “Andante con tenerezza.” But Ligeti soon turns toward his own dark and unsettling depths, from the slightly unhinged jauntiness of the “Vivacissimo molto ritmico” to the rough, herky-jerky “Alla marcia,” which sounds like nothing so much as marionettes being pushed around by some demented god. And all that is mere prelude to the wrenching “Lamento,” which closes the work — a searing, unblinking stare into anguish that tears the heart to shreds. An absolutely riveting piece and an unforgettable performance.

The players regrouped for Mendelssohn’s String Quintet No. 1 in A, Op. 18, a rapturous work written a year after the famous Octet — when the composer was still in his teens — and nearly as miraculous. The Marlboro players, led by Itamar Zorman on violin, turned in a performance so light and graceful it was nearly weightless, with detailed and utterly transparent playing.

Brookes is a freelance writer.