Natalia Osipova is an out-of-this-world Giselle. When she debuted the role with the Royal Ballet in 2014 it was a revelation, especially her second act where the dead girl rises as a wili (the spirit of a betrayed woman). She inhabited the ghostly being as if truly possessed, tossed into the air, breaking out of the music's frame and ballet's politeness to create something extraordinary. Opening a new season of the 19th-century ballet (Peter Wright's production, after Petipa), Osipova has lost none of her supernatural glow.
Giselle begins, however, a completely different being: the naive country girl. Bursting on to the stage, she couldn't be happier to greet the day with pure light and sweetness. She's a girl whose natural expression is dance - in fact, this whole act is infused with great joy in dancing, from Osipova carried away with buoyant grace; to the corps de ballet villagers, delighting in detailed petit allegro of the dancing-on-hot-coals variety, feet quickly escaping the floor; to the radiant pas de six, including a polished Joseph Sissens.
Giselle's downfall is noble Albrecht (Reece Clarke), the pair's dancing very much in sync. He woos her pretending to be an ordinary villager, although Clarke's tall, poised composure and capable strides could give the game away. Meanwhile, so natural is Osipova, you can entirely accept her descent into delusion having fallen irrationally in love and had her heart brutally broken in the space of an hour.
The painterly forest setting of Act II is home to the ice-hearted wilis (a stone-faced, precisely drilled corps). Osipova is transformed, the Romantic droop of her shoulders like an expression of defeat. When she moves, you could absolutely believe mystic powers are puppeteering her, rather than the dancer's own muscle and sinew - the awesomely high-springing jumps, the unfathomably smooth passage of head, neck and arms. Clarke executes a few mighty jumps of his own, as the wilis try to dance him to exhaustion.
Among the rest of the cast, a nod for Lukas Brændsrød, whose Hilarion is pleasingly unlikable, and Christina Arestis's Bathilde, Albrecht's aristocratic fiancee with a visible distaste for peasant life. They are small roles that matter, although there's no doubt this evening belongs to Osipova.
At the Royal Opera House, London, until 3 December. Live-streamed on 3 December.