Tchaikovsky's Nutcracker ballet and his one-act opera Iolanta seem unlikely companions, but their pairing by Welsh National Opera was authentic. They were originally commissioned by Russia's Imperial Theatres and premiered as a double bill, the difference here being that this was a concert performance. Staging Iolanta is not so much unfeasible as perceived inappropriate, its questionable libretto (adapted by the composer's brother, Modest) has the eponymous blind heroine restored to sight through a "Moorish" doctor. History damned Iolanta, as did Tchaikovsky, but in this full-on performance WNO showed the opera to be far from unworthy.

Conductor Vassily Sinaisky must take the main credit for going beyond the implausible plot and bringing out the lyrical passion. As in The Queen of Spades, Tchaikovsky is concerned with the symbolism of light and dark, and it is in Iolanta's innocent, implicit goodness and in the exalted vision of her Burgundian knight in shining armour, Vaudémont, that the healing power of love is invoked. Sinaisky has realised this most convincingly. Of the cast of 10, no one served him better than Nuccia Focile, singing the title role with wonderfully expressive tone and remarkable presence, managing the awkward business of the eyes subtly, so they could seem unseeing until opened by burgeoning love and the awareness of something beyond blind loyalty to her father, King René. Tchaikovsky suits Focile and this was her radiant best. As Vaudémont, Peter Hoare was fiercely ardent, his duet with Iolanta the opera's high-point.

WNO nearly sabotaged all the pluses by premiering this at Swansea's Grand Theatre - chorus and orchestra packed on to the small stage and soloists, seated in front, constrained by their characters being wrongly positioned in relation to each other. That resolved, there is every reason to catch it elsewhere.

· At Bristol Hippodrome on Thursday. Box office: 0870 607 7500. Then touring.