Ondine, Royal Opera House, London

Frederick Ashton's Ondine has always been tricky. This 1958 ballet, the tale of a water sprite and her human lover, is a weird mixture of invention and fussy nostalgia. Created for Margot Fonteyn, the lovely ballerina role is full of floating, rippling movement. But the heroine is surrounded by creaking plot development and padded-out divertissement dances.

In performance, Ondine needs all the help it can get. On this first night, the Royal Ballet wasn't doing much for it. In 2005, strong dancing gave Ondine real momentum. But director Monica Mason's conservative programming has left the dancers under-rehearsed and uninspired.

That doesn't apply to Tamara Rojo who dances Ondine with care and attack. She also catches the heroine's ignorance of human manners. Edward Watson, as the hero Palemon, lacks Rojo's drive and focus.

There's a better performance from Ricardo Cervera as the sea god Tirrenio. There's real fierceness in Cervera's darting jumps. As Berta, Palemon's human fiancée, Genesia Rosato is lively and malicious. The corps de ballet looks weak. As water sprites, they lack energy and precision. As huntsmen and Neapolitan dancers, they lack bite.

Ashton himself had difficulties with the score, commissioned from Hans Werner Henze. This shows in the interminable third act divertissement, when endless Neapolitan dancers appear to hold up the action.

Ondine is a retro ballet. Sometimes, the nostalgia is charming. In the second act's storm at sea, dancers sway in the balletic equivalent of Star Trek bridge acting. Ondine's flaws can be lifted by strong performance. This revival has a very long way to go.

To 6 December (020-7304 4000)