The Houston Ballet launched a two-week engagement at the Kennedy Center Opera House last night with an extremely handsome, interestingly unconventional "Swan Lake."

More than anything else, the evening was a tribute to the esthetic savvy and leadership qualities of artistic director Ben Stevenson, long familiar to Washingtonians as codirector of the vanished National Ballet in its last splendid years. Stevenson has been in Houston a decade now, and as last night's production and performance proved, he's transformed what was once a middling regional troupe into one of the nation's outstanding ballet companies. In "Swan Lake," which Stevenson first staged in this form in 1984, the company looked strong, vibrant and committed through all its ranks, easily equal to the heavy stylistic and technical demands put upon them.

If, nevertheless, the "Swan Lake" wasn't all it might have been, it was because so much depends on the lead casting. Li Cunxin, the Chinese-born dancer who has become a chief adornment of the troupe since his arrival in 1981, was in many ways an exemplary Prince Siegfried and an even more polished virtuoso than he seemed on the company's last visit three years ago. But he didn't look well matched with Janie Parker, the ballerina in the key, dual role of Odette-Odile, and Parker, formidable performer though she is, appeared out of her element as the Swan Queen. Parker, a gold medalist in international competition a few years back, is an exceptionally skilled dancer, but "Swan Lake," if it is to succeed in dramatic and emotional terms, calls for qualities that seemed to be outside her range.

All the same, in its conception, choreography and visual splendor, and in the totality of the company's performance, there is a very great deal to admire in this "Swan Lake." Stevenson's version is out of the ordinary, but not radically so. It's grounded stylistically in the Petipa-Ivanov tradition that has been the root of most western productions, but it's swifter, leaner and more compact -- two hours and 10 minutes with one intermission. Stevenson has compressed the original four acts into two uninterrupted halves. He's given us a Prologue set to Tchaikovsky's "Overture" music, shrewdly setting the tragic mood before the festive first act -- the idea's not new, but it's dramatically effective here. He's also given the Queen Mother more importance as a (nondance) role; made some cuts and reshufflings in the score; heightened the drama with some striking touches; and provided the Act III divertissements with a nice dramatic rationale by having the four Princesses -- candidates for Siegfried's hand in marriage -- come from four different nations corresponding to the musical styles Tchaikovsky invokes.

The designs by England's David Walker (who did the decor for Ashton's "The Dream," among other Royal Ballet productions) transport the action from its customary medieval ambiance to something vaguely, sumptuously 19th century. The advantages of having a single artistic impulse behind both sets and costumes are evident in the harmonious unities Walker achieves, in the autumnal arbor of the first act, the moonlit lakeside of the second and fourth, and the luxuriant palace ballroom of the third.

Cunxin danced brilliantly last night, his fine elevation, classical placement, beautifully centered pirouettes and soft, pliant landings making a noble picture indeed. Dramatically, he also exhibited regal qualities, but he seemed a bit subdued as a character, especially next to Parker, who rather overwhelmed him. His best moments were his big solos, ranging from the introspective meditation of Act I to the pyrotechnic dazzle of Act III.

Parker danced, for the most part, like a competition winner, with sturdy balances, eyepopping extensions and buoyant jumps. But she couldn't sustain the adagio of the crucial duet and solo by the lakeside, and though she was far more convincing as the steely Odile than the vulnerable Odette, the lack of inwardness and finesse proved damaging throughout. It was as if Esther Williams were attempting Camille.

The Pas de Six and Pas de Trois of Act I and the divertissements of Act III were excellently danced; the two solo Swans and the Cygnets in Act II also merit special commendation. The ensemble dancing throughout was praiseworthy, the more amazing since conductor Glen Langdon indulged in some extreme tempos -- dangerously slow in the lakeside scenes, and recklessly fast in the ballroom. On the other hand, he had the Opera House orchestra playing with fine ardor and precision.

"Swan Lake" will have five more performances through Sunday afternoon; a second cast of principals makes its bow tonight.