Beethoven and Falla. Only one conductor would dare to pair such radically dissimilar composers with the Philadelphia Orchestra: the late Rafael Frühbeck de Burgos.

Planned by him before his death last year, the program on Thursday fell to the orchestra's conductor in residence, Cristian Macelaru. He is as strong-minded as anyone standing before the orchestra this season and, overall, made the evening work in a manner hugely different from Frühbeck de Burgos'.

Beethoven was represented by his least severe orchestral work, the Symphony No. 6 ("Pastoral") whose 19th-century evocation of Austrian countryside could, in theory, intersect with Falla's reflections of pre-Franco 20th-century Spain. Under Macelaru, Beethoven was more rustic than suave, more robust than transparent. Entrances felt like announcements; exits didn't linger. Secondary melodies that many conductors would routinely let slip by sometimes had each note highlighted with their own messages. This was not Beethoven on meds.

Such touches kept the performance from slipping into mellifluous sameness: Although the composer created unprecedented descriptive effects here, he did so upon the simplest harmonic foundation of his symphonic life.

I particularly loved the way Macelaru set off new thematic directions with a nanosecond pause or a small crescendo that said, "Here it comes."

Once heralded, though, phrases within such theme groups were disappointingly treated like uniform links in a chain, in contrast to more historically informed performances that make individual phrases speak.

After intermission, Falla's The Three-Cornered Hat (Suite No. 2) was played not as a mere crowd-pleaser but, rather, projected many of the ballet's narrative details, which most conductors don't bother with. Bravo!

But that same sensibility nearly disassembled Falla's Nights in the Gardens of Spain, which was laden and elongated with more strongly characterized orchestral details than I ever thought possible. Pianist Jorge Federico Osorio exuded style and authority when his sound wasn't being covered up by the orchestra. A seasoned pianist, Osorio is only now making his Philadelphia Orchestra debut, and he's probably owed a re-engagement, and with something substantial, since he's one of the best Brahms pianists around.