A successful world premiere was the icing on the Washington Ballet's cake last night, as the company launched its fall series at Lisner Auditorium in a burst of youthful glory.

Indeed, the company is riding high these days. Choo San Goh, the troupe's resident choreographer since 1976 and a prime cause of its ascendancy since then, was recently promoted from assistant to associate artistic director, in a year that will have embraced the premiere of his first full-length ballet ("Romeo and Juliet," for the Boston Ballet) and a coming guest staging for the Royal Danish Ballet. Two days after the Lisner series (which ends Saturday), the company leaves for a three-week tour of South America, the first of two, perhaps three, overseas jaunts in '84-85, including one to China.

As always, the passage of a year has brought arrivals and departures among the dancers. But the new lineup looks to be, at first blush, possibly the finest thus far, and the eight men -- half of them trained in artistic director Mary Day's school -- certainly constitute the best matched, strongest male contigent one can recall in Washington Ballet history. Among the seven newcomers to the troupe, several already appear to be outstanding, including Cynthia Anderson, formerly of the Joffrey Ballet; Sandra Fortune, for years the leading ballerina of the city's now inactive Capitol Ballet; William Batcheler, a staunch young man from the Australian Ballet; and Amy Bauer, the latest of the extravagantly promising ingenues Day never fails to come up with year after year.

The premiere was "A Night at the Ballet" by New York's modern dance-trained Matthew Diamond -- at 32, already racking up direction and choreography credits for the Olympics, for Hollywood, for network TV and for musical theater. The new piece is of that comparatively rare genre, comedy ballet -- a kind of Murphy's Law of the dance stage, with everything that possibly can going dizzily haywire. The comedy is rather on the broad side generally, but except for one miscalculated gambit it doesn't depend on slapstick -- the humor comes from the movement, and most of it is very skillfully and cleverly engineered. The choreographic substance, moreover, isn't as slender as it might appear; it takes really cultivated craftsmanship to mimic all those ballet cliche's (and this is Diamond's first essay in the idiom), accurately enough to register and at a fast enough clip to keep the comic rhythm from flagging.

The music consists of three orchestral numbers by Emanuel Chabrier, and though the first is entitled "Danse Slave," somehow they all sound Spanish. The first movement begins with the four couples of the cast in a "here we are" exposition, the costumes with a touch of flamenco for the men and of "Don Quixote" for the women, including a rose blossom back of the ear. In short order the mishaps commence -- the ribbons on one of Lynn Cote's toe shoes come loose and start flailing around. When her partner Brian Jameson tosses the shoe offstage and it comes flying back from the wings, the audience knows what it's dealing with and laughter erupts, seldom to stop thereafter.

The second movement -- the most deft and original of the three, except for its overly blatant punch line -- has Elizabeth Guerin shyly in search of romance, and Batcheler as her distracted, reluctant prey, a sort of Prince Siegfried with a terminal case of wimpishness. The ballet is particularly apt as a showcase for its cast, and in the final movement, the other two couples -- Bauer, Dana Cronin, Thomas Terry and Robert Wallace -- get their turns in the limelight with a round-robin of collisions, tiffs and calamitous flirtations. "A Night at the Ballet" isn't the sort of piece you'd want to see more than once in a season, but it's decidedly a viable switch for the company repertoire.

Goh was represented by his 1978 "Double Contrasts," one of his technically most iridescent works, both reveling in and putting the spoof on voguish sophistication. The backdrop glitter has been exaggerated to excess, but the performance allowed Anderson, with her mock-hauteur and authority, to show just how polished and interesting a dancer she is; John Goding was her able partner, and Guerin and Batcheler were effectively contrasting as the couple in white.

Fortune and newcomer Greg Larson were smoothly paired in Charles Bennett's gymnastically intricate, amorous duet, "Albinoni Adagio." Vicente Nebrada's gaudy "A Handel Celebration," which opened the evening, was notable for solos by Cronin, Jameson and regal Julie Miles, as well as a ravishing duet for Bauer and Goding that underscored the former's poetic eloquence.

The evening's enigma was the size of the audience -- why a town like Washington can't fill Lisner for a company and a program such as this isn't easy to fathom.