In the classical world, great music can be the enemy of the excellent. Why schedule less-evolved Dvorak when later music is more accomplished?

That probably is why the composer's Symphony No. 6 had scant performance history here upon arrival at Thursday's Philadelphia Orchestra concert under music director Yannick Nézet-Séguin. The rather well-received program (to be repeated Saturday at the Kimmel Center) wasn't just a blow against classical redundancy, but a reminder that artistic Darwinism - the elusive process that dictates what lasts - needs to be upended periodically.

It's true that Dvorak's Sixth can sound like a mere template for the later symphonies, and in lesser performances, a bit plain and crude. But from Moment 1, Nézet-Séguin burrowed beneath the surface, finding tension in the underlying cross rhythms that gave the music an anything-can-happen rustle.

The big tunes were treated as expansively as possible - or so it seemed until, after a series of events highly differentiated with tempo and color, Nézet-Séguin risked an even broader tempo near the end of the first movement. The music had grandeur that reminded you how important this symphony is in its own right.

Brahms is said to have judged a piece of music by laying his arm across the middle of the score, evaluating only the treble and bass lines. Amid the Sixth's other movements (which sparkled and danced as you'd expect from Dvorak), Nézet-Séguin fashioned orchestral textures from that Brahms-ian perspective, and Dvorak came up trumps.

The concert began with The Moldau by Dvorak's elder contemporary Smetana, whose orchestration seems to capture Prague's particular brand of humidity in the light-timbred string writing near the end. I don't hesitate to describe the performance as magical.

The concert would have been significant if only for the appearance of elder-statesman pianist Radu Lupu, 68, who has recently struggled with pneumonia. Though Bartok's warm, lyrical Piano Concerto No. 3 doesn't require the force one hears from Yefim Bronfman, the lightness of Lupu's touch was strangely arresting, as if he were whispering the concerto. The performance also felt like chamber music, with Lupu contouring his phrasing and timbre to whatever incidental solo was coming out of the orchestra. I've never heard anything like it.

His sense of deliberation also felt technically unstable at various points. Would he make it? But what some pianists do with force he does with harmonic interruption.

Not everyone will go for Lupu's highly specialized experiment. Though I felt very fortunate to hear him, Lupu probably has better-rounded Bartok performances in his future.

Additional performance: 8 p.m. Saturday at the Kimmel Center, Broad and Spruce Streets. Information: 215-893-1999 or