No doubt the Library of Congress has had its share of artistic clashes over the years. However, the conflict last night between violinist Daniel Heifetz and pianist Dwight Peltzer almost overshadowed the main event, the first performance of a Serge Koussevitzky Foundation commission by the Pulitzer Prize-winning American composer, Donald Martino.

Certainly, the drama of the evening lay in the battle of temperaments rather than in the premiere. Peltzer and Heifetz may have been on stage at the same time, but seldom did they in any genuine sense play together. When a pair is so ill-matched both sides suffer, but Heifetz as the much more sensitive and subtle artist commanded greater sympathy. Deeply offended by the heavy-handed and -- in the case of the closing Franck A-Major Sonata -- less-than-accurate manner of Peltzer, Heifetz responded by playing as if he had no partner. An understandable, if not commendable, approach which brought the first movement of Mozart's B-Flat Major Sonata, K.454, to a dead halt.

When the duo took up again, Heifetz played with a frenzied intensity, finishing off phrases with a dagger-like thrust aimed musically if not physically at the pianist. Growing increasingly desperate, Heifetz turned the final movements of the Mozart and the closing Franck A-Major Sonata into a headlong race, and almost succeeded in losing Peltzer before the finish line.

Pianist Peltzer's performance in the two works with Heifetz makes one question -- despite the fact that Martino wrote the Koussevitzky Foundation commission for him -- how much of the music's seeming incoherence rested with his playing rather than the writing. Some of the very qualities lacking in Peltzer's partnership with violinist Heifetz were also missing in Martino's "Fantasies and Impromptus for solo piano."

Completed in January of this year, the piece came across on first hearing as maddeningly disjointed and devoid of any strong emotional impact. Despite Martino's high level of craftmanship and refined exploitation of pianistic resources, the listener was hard-pressed to link the succession of short pieces into a larger unity. Rather, there were effective moments, passages of strength and beauty, which seemed to exist in isolation. To be fairly judged the music deserves not only another hearing but, one suspects, another performer.