The Handel Festival Orchestra impresses the listener not only with the individuality of each musician (it is obviously more than the sum of its parts), but also with its superhuman ability to incorporate clearly and identifiably the personality of the baroque composers, in whose music they specialize, in every performance.

It isn't a very superstitious lot, either, scheduling a program beginning with obscure works by its namesake, progressing to a better-known Haydn piece, then to one of Mozart's most expressive and engrossing works; Friday the 13th at the Kennedy Center Terrace Theater turned Murphy's Law inside-out. If it could go right, it did.

The undisputed highlight was the very Mozartean Sinfonia Concertante in E-flat for Violin, Viola and Orchestra, K. 364, nearly flawless in execution. Soloists Jody Gatwood on the violin and guest violist Kim Kashkashian are superlative technicians and consummate artists. Closer to the modern solo concerto than to the baroque concerto grosso, the soloists played independently and together, unlike the concertino form prevalent in the other works in the program which contrasted the concertino group (two violins and cello) with the main body of the orchestra.

The program, with Stephen Simon as conductor, opened with a first performance in Washington of the rarely heard Overture to "Guistino" by Handel. The opera, first produced in 1737, was considered a failure, but the snaky interplay between oboe and strings was not, matching note-for-rote, what the composer intended. Haydn's Symphony No. 8 in G ("Le Soir") was invigorating; rarely does one hear such stylish bowing as Richard Frederickson's fat-sounding bass in the popular Menuetto.