While the National Symphony was performing in its usual habitat last night, its nearest rival was offering unusual competition a little farther uptown at the National Presbyterian Church. It seems that the Baltimore Symphony and its conductor, Sergiu Comissiona, have become quite fond of the acoustics in the church, which they discovered recently when searching for a suitable recording site.

After completing two discs there, Comissiona offered to bring the orchestra down once more for a public concert, an offer the church was only too pleased to accept -- especially when he decided to sweeten the deal with the Baltimore Symphony Chorus and four expert soloists. The result was an all-Haydn affair that showed off musicians and singers alike to great advantage.

For the extraordinary "Harmoniemesse," which contains some of Haydn's most persuasive music, Comissiona molded his forces carefully, encouraging an impressive transparency from the orchestra and a smooth, vibrant sound from the chorus. Soprano Benita Valente, mezzo Delia Wallis, tenor John Aler and bass John Ostendorf made an admirable quartet, particularly in the exquisite opening of the "Agnus Dei."

The concert began with a stylish account of Haydn's youthful Organ Concerto in C, with Ernest Ligon, the church's choirmaster, as soloist.