Cinderella, Royal Opera House, London

The Royal Ballet production of Sir Frederick Ashton's Cinderella, new last year, isn't ideal. Designs and staging are fussy; so much pedantic glitter. But the dancers and the ballet outshine their surroundings.

The fairy tale, revived for the Ashton centenary celebrations, was the choreographer's first three-act ballet. He made it for this company in 1948. It's a strange, dreamy version of the story. Prokofiev's score is full of tugging rhythms: urgent and hectic. Ashton's dances - variations for Season Fairies, dances for Courtiers and a corps de ballet of Stars - are pointed and brilliant. Beside this spiked classicism, there's a good deal of English pantomime.

As Cinderella, Alina Cojocaru gets better with every act. She's touching but quiet in her first scenes, dancing well but not quite in command of the music. Arriving at the ball, she has a new authority - head and shoulders grandly carried, with delicate use of her torso. Her feet aren't beautiful, but they're beautifully stretched. She glows in her dances with Johan Kobborg's Prince; grand and tender.

Back in her kitchen, she's a woman transformed. Her musical phrasing becomes more acute and playful. Dancing with her broom, she looks caught by Prokofiev's lilting waltz. Ashton's Cinderella wonders if the ball was a dream; finding her slipper, Cojocaru smiles with astonished, helpless radiance. Kobborg dances with buoyant attack and warm humanity. Ashton's hero has to do a lot of standing about. Kobborg spends it watching Cojocaru, gazing as if he can't quite believe her beauty. His solo is cleanly, exuberantly danced.

Wayne Sleep and Anthony Dowell are the first-cast Ugly Sisters. They're strong stage presences, but there's too much knowing drag. It leaves little room for spontaneity or warmth. Ashton made his sister almost tragic - not so much bossy as mean, with a sour gooseberry face - but I can't feel sorry for Sleep's. Still, I like the way Sleep uses his famously small stature, jumping into the air to kiss Dowell's cheek. Dressing up, he has a look of absurd satisfaction with his new frock.

The ballet's classical side now works better than its comedy. Vanessa Palmer is a gracious Fairy Godmother, with fluent line and vivid upper-body detail. As the Summer Fairy, Lauren Cuthbertson dances with full, rich phrasing. Laura Morera is a quick, crisp Autumn, tearing through off-balance pirouettes.

Wendy Ellis Somes' production does get in the ballet's way. Designs by Toer van Schayk and Christine Haworth are all messy detail, with some lurid colouring. The steps are there and they're wonderful, but the staging often goes against the ballet's spirit. Cinderella's ballroom entrance should be a magical moment. She comes in alone, walking slowly down the steps - Ellis Somes surrounds poor Cinders with footmen. Some of that pedantry affects the dancing. The Stars dance correctly, but those spiky steps need bolder attack. They're not helped by Boris Gruzin's unimaginative conducting. The corps are much better in the ballroom scene, sweeping through those graceful, intricate dances.

In repertory until 14 January (020-7304 4000)