Winter still has its grip on St Petersburg. There is ice on the Neva, the canals are frozen, and brilliant sun alternates with driving snow and frozen pavements. The gold spire of the Admiralty building catches the wintry light, and so it does in Alexandre Benois' design for the fair in Petrushka, one of the works in the second Mariinsky Ballet Festival which began last weekend. Ten evenings, foreign stars - several from the Paris Opera - and programming which shows how the Kirov troupe is bridging the two worlds implicit in its own miraculous history and in the need for fresh creative ideas, especially from the west.

As in the city itself, the new is making its mark in the ballet. Under Makhar Vaziyev's direction, regeneration is careful and - so its seems to me - alert to possibilities as well as to dangers. The task lies in the quest for creative talent from within the ensemble, heirs to Fokine, Balanchine, Nijinsky, and to such vital choreographers of the Soviet era as Lavrovsky, Zakharov, Grigorovich.

An attempt was made last year with Kirill Simonov's Nutcracker, and this season there is a new version of Cinderella by Alexei Ratmansky, Kirov trained but based in Copenhagen. Alas, I thought the staging, first shown a week ago, to be a fearful let-down. Ratmansky has set the action in modern times (Cinderella's home is a bare space surrounded by skeletal ladders and scaffolding: dusting must be quite a problem) and has eschewed any feeling for domesticity, for the fairy-tale magic and wide-eyed romance which warm the tale and Prokofiev's score - which is surely the best he wrote for ballet, and which pays homage to Tchaikovsky at every turn.

Apart from Cinderella, a role taken with gamine charm and ravishing style by Natalya Sologub, the characters are coarse cyphers: Step-mama is a tarty harridan, the sisters are nonentities, Pa a tremulous lush. The fairy-godmother is a bag-lady; the season-fairies are four chaps with painted faces and numbingly un-musical variations; the ball a dismal hop peopled by grotesques. The waltzes, with their irresistible extra-sec melodies, go for nothing. Ratmansky's dances are starveling things, and the drama seems inconsistent (I shall never know why the Prince has to show Cinders' shoe to a group of chaps who, whatever else their proclivities, are not drag-queens). The duets for Cinderella and her handsome Prince (a handsome and gifted Denis Matviyenko) would suit pair-skaters. Nothing, except for the adorable Sologub, touches the heart or mind. And it all is markedly glum in design.

Far better things - exquisite dancing; wildest passion; crowds of revellers; eunuchs and sylphs and a nicely timed massacre, plus the Admiralty spire and falling snow - came with the next evening. It was, as you may surmise, devoted to Ballets of Mikhail Fokine, though there should have been the subtitle "Well, up to a point Lord Copper". The opening Chopiniana was as near perfect as I dare to hope. The production has long been a gem in the Kirov repertoire, Fokine is unadulterated, and it is danced with an ideal understanding of its dreams, its romanticism - the dancers not moping, as in most western productions, but sweetly aspiring, light in spirit as in step. Zhanna Ayupova was sublime as its central figure, every movement caught on the night breeze, and Vladimir Malakhov was admirably right in mood and impeccable in technique, with strength and mellifluous phrasing combined.

Then Scheherazade, or a madcap simulacrum thereof. The Bakst set looks reasonable and glows with macaw colours. The Kirov's artists know exactly how to make sense of the hot-house emotions of the harem - Vladimir Ponomarov's every gesture as the Sultan has silent-cinema power - and Nikolay Tsiskaridze (a guest from the Bolshoi) joined Irma Nioradze in the most extravagantly erotic piece of scenery-chewing any devotee of camp could desire.

Nioradze is a very intelligent actress - we believe in this Zobeide from the very first as spoiled, petulant, commanding. Tsiskaridze, released from the slave's quarters, bursts upon us (and Zobeide) in a sub-Bakstian fantasy of gold and black, sequins, jewels, pearl shoulder-straps and a torrent of dancing.

Heaven, and the ghost of Mikhail Fokine, knows what all this has to so with the original Scheherazade, but these artists blazed with lust, and generated enough passion to show that though this mad old ballet is a turnip ghost in other hands, when danced with such imaginative bravura, such sexual allure, it goes beyond hilarious kitsch to become theatrical art of the most intoxicating kind.

Nioradze makes every pose a declaration of sexual allure. Tsiskaridze, as much in love with his audience as with Zobeide, produced marvels of pantherine leaps and crouching consumed-by-desire falls, and tore the place apart. It may not be Fokine, but who cares?

And finally Petrushka and the Admiralty spire - which was the most likely thing about the event. Staged in 1920 by Leonid Leontiev from his memories of the original Diaghilev production in 1911, it is staggeringly unlike the Petrushka we have known from those producers and dancers who appeared in the original. The Kirov troupe play the crowd scenes with effortless skill and understanding: we see the Butterweek Fair as Benois and Fokine intended. The choreography and motivations for the central trio of Doll, Petrushka and Blackamoor are, quite simply, inexact, vulgar. Not even the artistry of Zhanna Ayupova, Vladimir Malakhov and Islom Baimuradov could rescue the affair. The Kirov owes it to one of its greatest sons to revert to the original Diaghilev text.