The legendary Vaslav Nijinsky was known as the God of the Dance, but as choreographer John Neumeier makes clear in his ballet inspired by the Russian dancer, his life was ruled by distinctly mortal forces: love, sex, creativity and deep, unglamorous pain.

But Neumeier's "Nijinsky," which the Hamburg Ballet performed Wednesday at the start of a five-day run at the Kennedy Center Opera House, does not exploit the salacious aspects of the dancer's life. Nor is it morbid. It is, in fact, a singularly engrossing ride through an imagined world, one in which celebrated dancers, Parisian society and characters from long-ago ballets mingle with hallucinatory force.

With its casual, unceasing shifts of time and place, a complicated cast of characters -- and with Nijinsky himself split into half a dozen personalities -- this two-act, evening-length ballet ought not to work. Yet imperfect as it is, it succeeds as dynamic, rich and gripping theater.

Nijinsky is one of the art world's most tragic figures, an extraordinary virtuoso who became an international celebrity in the early 20th century while dancing with Serge Diaghilev's Ballets Russes. Fame did not ensure his happiness, however, or even his career. Diaghilev, his boss as well as his lover, fired Nijinsky after the dancer unexpectedly married. He rarely danced again, and spent almost three decades in mental institutions.

Background knowledge of Nijinsky's life is helpful, but not essential, to following the ballet. The point of departure is Nijinsky's performance at a Swiss hotel in 1919 -- a performance that was to be his last. Jiri Bubenicek portrays the visibly nervous, wary Nijinsky, who nevertheless bursts with expressive force once he starts to dance. Yet what begins as a controlled, polite gathering quickly dissolves into a reverie taking place inside Nijinsky's head, as key moments in his life and scenes from his ballets materialize onstage.

Chief accolades go to Bubenicek, whose feral intensity gives the ballet much of its power. His focus never dims throughout a draining performance full of sustained poses, surprising airborne explosions and luxurious sensuality. His technical qualities are considerable: high, easy extensions, amplified shapes, extraordinary jumping height and quick revolutions in the air that give his dancing brilliance. But his magnetic stage presence is equally impressive. A slender man with delicate features, he looks nothing like the stocky, muscular Russian, but it is easy to believe that he dances with a like power.

Bubenicek's identical twin, Otto, performs with an arresting elasticity and similar authority in one of the ancillary Nijinsky roles, as the Golden Slave in Michel Fokine's "Scheherazade," a blockbuster hit for the Ballets Russes that sparked a cult following. Other dancers drift on to represent additional roles Nijinsky made famous: the Spirit of the Rose in "Spectre de la Rose," and characters from his own, pioneering choreography such as "L'Apres-midi d'un faune" ("Afternoon of a Faun") and "Jeux."

In his own works, the greatest virtuoso of his day rejected technical feats for a more stylized and coarsened approach. Though these works are, for the most part, lost -- no authoritative record of them remains aside from photos, sketches and notes -- Neumeier re-creates their modern, angular look with great efficiency.

Impresario Serge Diaghilev, performed by Ivan Urban, is a sinister figure, icy and inscrutable in his tuxedo, and his power over Nijinsky is absolute. Whenever he appears, the young dancer becomes melting and needy, literally swooning in the older man's arms. This characterization feels thin; surely their relationship was more nuanced than that of puppeteer and marionette. Yet Diaghilev does serve as an effective narrative device, appearing out of the darkness to drive the young man crazy just when Nijinsky is caught up in a happy swirl.

The cast is excellent across the board. Strong classical training gives a crisp edge to the variety of dance styles that Neumeier incorporates. Especially wonderful are the dramatic depths they add. You can feel the dancers' total emotional involvement, and this is what draws the viewer in.

Particularly notable is Anna Polikarpova as Romola Nijinsky, the dancer's wife. A willowy blonde with beautifully supple feet, she is also an expressive actress. Her role is a sympathetic one, but it is complicated: She is a woman who came to love the man after falling in love with his dancing -- she is frequently seen draping herself over the ballet-role Nijinsky figures, or kneeling at their feet as if in deference to their art.

The tight drama of the first act slackens in the second, and this is one of the work's problems. Once Nijinsky leaves Diaghilev, he becomes less interesting. His battles with mental demons are poignant, but difficult to convey theatrically. (Romola drags him around on a sled, apparently evoking her travels through Switzerland in search of psychiatric help.)

Adding to the greatly diminished tempo in the second act is Neumeier's choice of music: excerpts of symphonic works by Shostakovich that have a more subdued, meandering quality than the forcefully punctuated Rimsky-Korsakov "Scheherazade" that drove the first half. A highlight is the electric, hungrily focused performance by Yukichi Hattori as Nijinsky's brother Stanislav, who was also mentally ill.

Neumeier brings his knowledge of the era to bear in the costumes, which he designed. There are the flaming oranges and bright melon-colored harem pants inspired by the ballet "Scheherazade," while Parisian patrons are dressed in elegant black and white. The stageful of soldiers, evoking World War I, wear open jackets over bare chests and snug, very brief briefs, forming a risque regiment.

While judicious trimming would improve this act, the ending presents a movingly intimate picture of torment that will not soon be forgotten: We return to the Swiss hotel of the opening, where we see the crowd through Nijinsky's fevered eyes. The guests are climbing on the balustrades, shouting and jeering. Characters from his ballets drift in and dance in a phantasmagoric whirl. In the midst of this nightmare, Bubenicek shifts in his chair, his cheeks sunken, his eyes burning but vacant.

What passed through the mind of the artist at this moment we will never know. But in the course of this extraordinary evening, the shattering of a man, and the utter devastation of his existence, is made searingly plain.

Led by conductor Rainer Muhlbach, the Kennedy Center Opera House Orchestra did a fine job with the symphonic works.

Performances of "Nijinsky" continue through Sunday, with cast changes.

Hamburg Ballet's Otto Bubenicek as Nijinsky and Anna Polikarpova as his wife.The Hamburg Ballet creates two worlds for Vaslav Nijinsky: one real, and one in his head. "Nijinsky" is at the Kennedy Center through Sunday.Otto Bubenicek's Nijinsky swoons for lover Serge Diaghilev (Ivan Urban).