Oppressive rainfall didn't deter an overflowing crowd from pouring into the Phillips Collection recital yesterday afternoon to hear Boris Slutsky, the winner of the 1981 University of Maryland International Piano Competition. Why the great majority of listeners bothered to attend is a mystery, because the reception they accorded the young red-haired pianist most of the time can best be described as listless.

Perhaps that is why Slutsky's performance was mostly the same. The normal give-and-take of the artist-audience relationship sadly lacked the energy a performer absorbs in live performance.

Slutsky tried to placate the waterlogged listeners with a flood of expert and heartfelt pianism. His performing style is intriguing: he arches his eyebrows and raises his eyes heavenward, as if pleading to his personal muse.

The inner vigor of Slutsky's style was apparent from his opening selection, Bach's "Italian Concerto," with its crisp phrasing, yet it warmed up Slutsky more than the audience. He concluded the first half with Prokofiev's Sonata No. 7 in B-flat Major, which sometimes disintegrated among the lower octaves into slush.

The second half featured six works by Chopin, a composer for whom Slutsky's temperament is well matched. The mood of the chosen works, however, was the same. Instead of six distinct pieces, the impression was that of six movements of one composition. The exception was the Scherzo in E, Opus 54, with Slutsky's emphasis on the burning tempo and sudden shifts in dynamics. Slutsky has the capacity to dazzle, yet he did it sparingly, waiting until the second encore before truly enjoying the enthusiastic roar of approval.