Modern dance or stand-up comedy?

The Philadelphia Orchestra blurred that unlikely line in a Thursday performance of Stravinsky's ballet Petrushka that showed how laugh-out-loud funny the piece can be in a mordantly Russian kind of way, but also how modern it truly is, and in ways that suggest the more infamous Rite of Spring may not have been such a leap forward in the history of classical music, but a leap to the side.

In other words, week two of the Philadelphia Orchestra's Paris Festival definitely woke up, with a business-not-as-usual Petrushka and an unprogrammed surprise, the little-known Debussy-influenced D'un matin de printemps by Lili Boulanger, whose animated exterior with rustling undercurrents made it a perfect concert opener.

Boulanger was also the only native French composer on a program filled out by Chopin's Piano Concerto No. 1 (written in Poland before the composer's migration to France). Whether or not the program fit conceptually, it worked artistically on every level.

The Stravinsky performance was a model of revisionist thinking that also sits easily within the preestablished perimeters of the piece. The best orchestras struggled for decades just to achieve a polished rendering of the piece's carnival of effects, many presented simultaneously with flights into bitonality. Music director Yannick Nézet-Séguin went several generations beyond that. Though many conductors rightly perform the work as an abstract orchestral showpiece, Nézet-Séguin embraced the score's original purpose, as musical narrative about an obnoxious puppet and the world around him, assuming the orchestra must tell the story completely on its own because choreographed dancers aren't on hand to do their part.

In effect, the performance was like a radio play that conjures a visual story without actually being visual, mainly because the physical motion implied by the music was shaped in ways that implied much psychology behind it. The piece also felt more modern than usual, with off-kilter and frequently changing meters strongly pronounced, giving the music a constantly shifting floor plan. Overall contours were jagged and steep, with peaks of tension followed by expansive solos that were given the time and freedom to explore the ballet's scenario in ways that seldom happen. All sorts of pockets emerged, like an exchange between bassoon and piano I had never detected in my decades with the piece.

Similar interplay was attempted during the Chopin concerto, and Louis Lortie was certainly the kind of piano soloist to work with such an approach. His cool, luminous sound readily revealed conversational phrasing that was unceasingly poetic, more dreamy than vigorous, and always rendered with the utmost sympathy for the music. But where Nézet-Séguin made the orchestra answer back to the pianist, the orchestration didn't offer much to say. Beautiful as the music can be, the piece is borderline juvenilia, still worth hearing with an artist of Lortie's caliber, though one should never expect too much from it.

The program will be repeated at 8 p.m. Saturday at the Kimmel Center. Information: 215-893-1999 or www.philorch.org.