Maybe he didn't realize when the program was devised that the orchestra was looking for a music director. Maybe he's just so single-minded in his musical zeal that splash-making doesn't occur to him. Nonetheless, Gatti's Thursday outing with the orchestra, which he topped off with Brahms' Symphony No. 1, left little doubt: He's a contender, one with more age (47) and experience than some of the others, plus a wide repertoire and a sure instinct for projecting the DNA of any given piece.

The Italianate qualities of Rossini and Mendelssohn were intelligently differentiated: The former had a sense of the pit-orchestra scale for which the music was conceived. Phrases were clipped but amiably inflected, without the extraneous cuteness that trivializes the music.

Mendelssohn can seem like a musical chameleon - Scottish one minute, Italian the next - though not with Gatti, who firmly rooted the music in the refined classicism of Mozart. With less-driven tempos than what's usually heard, Gatti revealed an only somewhat refracted version of the composer's Midsummer Night's Dream manner. With less-driven tempos, normally glossed-over pockets of music revealed themselves. Were cuts restored? It felt that way.

Gatti's authority with Brahms isn't to be taken for granted. Simon Rattle and Vladimir Jurowski are just two conductors who haven't gotten their arms around the composer's most heterogeneous symphony recently. Even Gatti has been guilty of laboriousness. But with a solidly conceived tempo scheme, each event had its due while keeping everything in balance. Nothing dragged due to the helium effect of the Philadelphia sound.

Initially, Gatti appeared to paint himself into a corner: Having reached what seemed like peak saturation with the orchestra's string sound in the first movement, how could the rest not be anticlimactic? Yet the sound picture grew in scope and intensity without curdling into strident overkill. This was Brahms of utmost seriousness: No postmodern observation, no school of performance, just whatever it takes to achieve maximum meaning without wringing the piece dry.

Principal players seemed drawn into that spirit: Incidental solos by hornist Jennifer Montone, clarinetist Ricardo Morales, and concertmaster David Kim exuded nobility without pretention. The experience was so abundant, you didn't want to hear anything else for a good while.

Lucky for Gatti, tonight's repeat performance at the Kimmel Center comes after his Metropolitan Opera matinee of Aida (which will be simulcast in local movie theaters). Were performance times reversed, facing Aida after this kind of Brahms might be impossible.