Morris throws a wild party

Onstage at the War Memorial Opera House, the virgin huntress Sylvia is trapped, locked in a cave with her lustful kidnapper, Orion, and a crew of slaves who might be the offspring of either the trolls in Bournonville’s “A Folk Tale,” the Siren’s servants in Balanchine’s “Prodigal Son” or Disney’s seven dwarfs.

Her situation is desperate but also increasingly hilarious as she gets everybody drunk on new-made wine and dances outlandish parodies of exotica to fend off amorous advances. Here -- at last -- Mark Morris’ talents for choreography, for comedy, for throwing a party to the most unlikely music come together in one lunatic bacchanal.

Otherwise Morris’ brand-new production of the vintage three-act story ballet “Sylvia,” the first staging by any American company, remains uneven and curiously sedate. This is his only non-operatic full-evening project since “The Hard Nut” in 1991, and he is no longer an inspired, imaginative artist but rather a supremely clever interpretive one.

Working with the accomplished dancers of San Francisco Ballet and a distinguished production team, he has produced a flawed, entertaining “Sylvia” that aims to respect the spirit and style of Leo Delibes’ 1876 score as well as the contours of the original plot. Set in ancient Greece, that plot shows a powerful, independent woman brought low by male brutality and her own pride but restored to happiness (if not self-sufficiency) by Eros, god of love.

Morris clearly enjoys the ballet’s gender reversals -- an active, resourceful heroine (Sylvia) devoted to hunting versus a passive, dishy hero (Aminta) devoted to romance. He has also worked hard and well to make the pantomime passages clear, urgent and absolutely natural.

But a conflict between the demands of storytelling and music visualization develops right away, with some of Delibes’ most delicate music trampled by the bravura stunts of the satyrs just after the curtain rises. Moreover, in the next scene, Morris’ by-the-numbers choreography for Sylvia and her nymphs simply cannot touch the grandeur of one of the great fanfares of all time.

Besides the comedy, the large-scale divertissements work best, with Morris adding accents and embellishments to freshen the ballet vocabulary. In Act 3, for instance, two heralds execute little hops in a circle that blossom into classical turns, an inventive, charming motif. But in weightier passages, Morris serves the score’s rhythms and structures more successfully than its power or emotion. Character portrayals can also prove troublesome, no matter which of three casts one saw during the premiere weekend.

Yuri Possokhov, Pierre-Francois Vilanoba and Peter Brandenhoff danced Orion, and made him so endearing in his hopeless passion for Sylvia that his badly staged demise didn’t so much resolve the plot as confirm Morris’ weakness as a director.

Although the title role showcased Yuan Yuan Tan’s lyric purity on Friday and Vanessa Zahorian’s technical ease on Saturday night, corps dancer Elizabeth Miner bridged the extremes with a special flair at the matinee.

Miner also had the advantage of the sweetest, most persuasively lovesick partner: Pascal Molat as Aminta. Gonzalo Garcia danced the role intently at the premiere and Joan Boada conveyed the joyous freedom of love on Saturday evening, but Molat danced his heart out, and it made the ultimate difference.

Up from the corps, Garrett Anderson, Pablo Piantino and Jaime Garcia Castilla made the most of the prominent dramatic and choreographic displays assigned to Eros, with Castilla adding a boyish whimsy all his own. Muriel Maffre and especially Lorena Feijoo proved superbly domineering in their star-cameo as the goddess Diana. But the impact of the interplay between gods and mortals in the finale depended less on choreography, staging or the dancers’ performances than on the commanding musicianship of the San Francisco Ballet Orchestra and the remarkable authority of conductor Andrew Mogrelia.

Designers Allen Moyer (sets) and Martin Pakledinaz (costumes) both prioritized bold color and intricate decoration. But major lapses needed reconsideration. Each scene included an elaborate production effect that seemed a valentine to antique stagecraft: Sylvia on an enormous garlanded swing, an impossibly huge boulder rolling across the mouth of Orion’s cave, a ship laden with harem beauties sailing into view.

However, all the many supernatural transformations and bow-and-arrow effects that drove the plot were staged and designed with no sense of magic whatsoever. Moreover, some of the costumes undermined the dancers’ credibility, most notably the golden tunic worn by Eros, which looked like a low-cut ‘20s flapper dress.

Morris’ erratic “Sylvia” was certainly fun, but it’s good to know that the Royal Ballet will be reviving the neoclassic Frederick Ashton version later this season.

Performances continue through May 9.