So much of the success of Willy Russell’s ivory-spired two-hander rests on the chemistry between its actors. The play traces a woman’s self-empowerment through education via her relationship with a world-weary Open University academic, but there is stiffness here between Rita (Alexandra Mardell) and Frank (Dominic Mafham) as they get acquainted.

Frank learns of Rita’s desperate ambition for life beyond her job as a hairdresser and role as wife. Rita hears about his history as a published poet – and picks up on his inveterate drinking. In director Cara Nolan’s production, the dynamic between the pair does not pop in the early scenes, not through any lack of trying, especially on the part of Mardell. She makes a broad, vivacious scouser who has enrolled on to an English literature Open University course in hope to expand her intellectual horizons.

The humour is sluggish and the pace is plodding, but whatever failings this production presents in the first half are redeemed in the more vibrant second. Funny lines finally zing, Frank’s quiet despair moves you – and so does Rita’s transformation. It is admirable that their dynamic never sinks into a lazy subtext of romance between them. Frank may hint at his attraction for her (he did, after all, fall in love with a former student with whom he now lives, he tells her). But what Rita and Frank have is something platonic, yet loving. He is not a Henry Higgins figure; she changes him as much as his lessons in critical thought and literature mark her.

Russell has a lovely facility for writing female subjectivity and as a play about a woman finding her voice, academic and otherwise, it holds its classic status. Rita is a compassionately drawn figure who comes into her own power and redefines her life.

The play premiered in 1980 and the original setting is kept by Nolan (with an old-style trilling phone and era-specific references), yet the overarching message is still relevant, from the societal pressures on young women to have babies (exerted quite literally by Rita’s husband here) to self-determination and the endeavour to discover what freedom looks like outside of class and social expectation.

• At Curve theatre, Leicester, until 17 October