Mozart's K 467 Concerto offered C major unsullied by clusters, but deliciously spiked with chromaticism.
Stier caught its mock serioso mood with an exposition that was a model of nuanced orchestral playing.
There was also a gentle humour underlying Schirmer's pearly passagework, sneaking in a mini-cadenza within seconds of her entrance.
Stier emphasised harmonic pungencies in its celebrated Andante, while Schirmer let her melodies float and soar in graceful arches.
Humour took over again in the Finale, especially when the pianist dashed through a free-roving jazzy cadenza, earning a gender-insensitive cry of "Bravo" from the hall.
A clever encore had Stier and Schirmer sharing the Steinway and making a party piece of a Brahms Hungarian Dance.
Shostakovich's Twelfth Symphony is not the subtlest of symphonies; a symphonic deification of Lenin, written at the height of the Cold War.
While some irony meters may have gone into overload, it was easier to submit to the uninhibited clash and clangour of it all, from snaky themes peppered with percussion to much orchestral shouting in the key of D.
It was a full-on 37-minute adrenalin roll, and the best argument possible for securing your seat for the orchestra's 2015 season.