South African writer/director Yael Farber has taken successful reinterpretations of classics around the world before. But none has had the impact of this updated Strindberg.

Farber has re-energised the Swedish dramatist's 1888 play with a political and sexual charge. The setting is not an aristocratic house but a South African farmstead. And the barrier that keeps the owner's daughter Julie from being with John - the male servant with whom she flirts to the point of forbidden consummation - is not just status, but colour.

It's Freedom Day, which in modern South Africa marks the moment when such barriers are meant to no longer exist. But like much of the country, this farm's land in the arid Karoo is owned by whites, and worked by blacks.

This isn't the first attempt to modify this dated play. Patrick Marber's version set it in post-war England. Farber's work though has the feel of a definitive re-imagining. The character of Christine has been changed from John's fiancé to his mother (Thoko Ntshinga) which only adds to the obligations expected of her son. Julie is similarly attached to her (unseen) father, "the master" who, she tells John, would shoot the black man who touches her. Then she entices him to dance.

Getting out of this kitchen if it gets too hot is not an option. Hilde Cronje's Julie, wearing a skirt with a thigh-length split, turns up the heat to a level that drives Bongile Mantsai's muscular John to distraction. Sexual chemistry doesn't say it. This is fission. Mantsai and Cronje are superb, the latter flashing Boer tough-as-nails pride and then a tenderness that cannot survive in this wilderness.

None of this would mean much however if Farber's version didn't fit so well into this context. Often, updating a play asks audiences to turn a blind eye to characters whose behaviour is better suited to the period for which they were created. It was this credibility gap that prevented Benedict Andrews's recent updated version of Chekhov's Three Sisters from firing on all cylinders.

Here, every action and word feels true. As does the bleak mood of the piece - a mood embodied by an unforgettable Tandiwe Nofirst Lungisa who plays a spiritual figure, intoning ancient music as she walks the farm's perimeter.

This Strindberg play hasn't just been updated, it's been immortalised. (www.riversidestudios.co.uk)