The Washington Ballet's program at Lisner Auditorium last night, highlighted by the world premiere of Choo-San Goh's "Unknown Territory," was a giant step forward both for the company and its resident choreographer.

At the start of the '85-86 season last October, the company seemed under a pall, induced partly, one would guess, by the exodus of so many dancers and a corresponding influx of newcomers. Since then there have been the "Nutcracker" performances and some touring. By whatever means the feat was accomplished, the company now looks transformed. Once again a sharp, integrated ensemble, the group appears to have recaptured nearly all of the cohesion, sleekness and spirit that marked its best years of the recent past.

"Unknown Territory" demonstrates pointedly that Goh's creative evolution is far from over. Every two years since his arrival in Washington in 1976 he's come up with a breakthrough of sorts: the propulsive abstraction "Fives" in 1978; the distilled romanticism of "Lament" in 1980; a fusion of these contrary impulses in the 1982 "In the Glow of the Night"; his first full-length narrative work, "Romeo and Juliet," in 1984 (for the Boston Ballet); and now the richly exotic "Unknown Territory."

This is the first time Goh has collaborated actively with a composer -- Jim Jacobsen, a 30-year-old, Arlington-born musician now resident in Chicago. The experience seems to have been a liberating one.It's as if Goh, within minimal classical constraints, let his fantasy run free, and at the same time permitted the ever latent impulses of his Chinese lineage to rise fully to the surface. The outcome is a sort of Orientalized "Les Noces" -- a primitive wedding ritual that seems to be reconstituted from some ancient, mythical eastern dominion.

As Jacobsen's music prepares the atmosphere with a tense electronic drizzle, the curtain rises slowly to reveal Carol Vollet Garner's striking set and costumes. The backdrop is a dark, stylized sky, with slender, leaved branches curling into an immense golden sun. Against this, the dancers are frozen into a tableau -- the men, in halters and briefs, on one side; the women, in streaked unitards, on the other, the predominant colors red and black. Upstage center, two handmaidens flank Janet Shibata as the bride. Caught in the varnished gleam of Beth Newbold's canny lighting, the whole picture looks like a lacquered Chinese painting come to life, and murmurs of appreciation swept through the audience at the sight.

The tautly composed ceremony begins with an introductory ensemble showing typical insignia of Goh's past choreography -- angled or serpentine arms, odd flexions of the torso, a hand held at the back of the head with splayed fingers, like a spiked coronet. These images, always somehow Chinese in graphic contour, are no longer peripheral, butcentral and crucial to the dance design. In the next section, the handmaidens manifest their adoration of the bride. She moves forward, and they unwrap the cocoon of gilt-threaded cloth that coils around her. The men kneel before her, and then prostrate themselves like a ring of reclining lions. She dances a solo marked by snaking arms echoed in the ensemble.

The groom (John Goding) enters and dances a sensuous duet with Shibata in which she teases him with rocking head motions and he pursues her in spectacular dives to the floor. There follows a men's dance full of jumps, dives, contractions and body slaps. As the women again move to the fore, rippling their torsos suggestively, the ballet races to its culmination. Men and women smack together, and at the sacramental climax, bride and groom are pushed into collision. Concealed from our eyes by a writhing mass of bodies, they seal their match, igniting the rest of the clan into a frenzy of erotic writhings and couplings. The music thus far has been an exotic fluctuation of drones, ostinatos and percussive poundings; now it quiets to a mysterious shimmer as the nuptial pair are wrapped in a symbolic red banner. In the coda, the banner is severed, and at the signal of a bell chime, the bride is raised aloft. A second signal, and the groom takes his leave, off, as a program note puts it, "to prove his manhood," presumably in the hunt or in battle or some such endeavor.

In verbal description, this may sound somewhat hokey, but it's not at all that way in the flesh -- a tribute to the austerity of Goh's artistic vision. Instead, the ballet generates an increasingly mesmerizing intensity, much abetted by the dancing of Shibata, who reveals a new capacity for erotic insinuation; by Goding, who looks more incisive in this part than in any previous role; and by the ensemble, with its unremitting electricity of attack. The crowd gave the work a cheering reception, and Goh, Jacobsen and their creative collaborators a noisy ovation.

"Unknown Territory" was the revelation of the program, but it was by no means the end of evening's rewards. The company was also seen to excellent advantage in the known territory of Goh's charmingly neoclassical "Schubert Symphony," featuring Lynn Cote and Michael Bjerknes, and in a particularly impassioned, lyrical, precise but never edgy performance of Balanchine's "Serenade," led by Elizabeth Guerin, Julie Miles, Cote, Bjerknes and Goding.

The program will be repeated tonight and tomorrow.