What's Doctor Faustus in a secular age? What does it mean to sell one's soul to the devil, if you don't believe that either exists? Maria Aberg, the liveliest director in the RSC's stable, comes up with a compelling answer in a compelling production.

It starts with a match – two, in fact. Oliver Ryan and Sandy Grierson, mirror images of one another in matching black suits, pick their parts by chance. Whoever's flame goes out first, that's Faustus. The other man is Mephistophilis. It's as rich an image – play with fire and you'll burn your fingers – as it is a conceit. Here, there's no separating devil and doctor. Each contains the other, so that Marlowe's spiritual world becomes an expression of the self: the devil as a kind of depression, the darkness of which we're all capable.

That's born out by the text. Faustus turns to black magic because he's run out of purpose. Ryan, in the part on press night, takes a Stanley knife to his forearm to sign over his soul, then, when his blood clots, follows up with a match to his skin. His Faustus is bitter as black coffee, so clenched and convulsive. He drinks perpetually, and his pentangle – slowly slashed onto the stage in white paint – is as punk as they come. "Where we are is hell," advises Grierson's lithe Mephistophilis, "and where hell is must ever we be."

It's not a glib shift either: devil, depression, lalala. It's actually profoundly moral, even theological. Aberg implies that rather than sell his soul, Faustus damns himself by his actions. He leads himself into temptation. It's an intricate reversal: the earthly pleasures and powers aren't a downpayment, but a trap.

The Seven Deadly Sins aren't just repulsive, then, they're enticing and erotic; a Torture Garden of glittery gladrags and fetishwear. Lechery's a drag queen. Envy's in a gimp mask. They look like the best night out on the planet. Naomi Dawson dishes up a carnival of grossness: a pot-bellied pope in pyjamas, lords and ladies in bulbous fat suits, an army of faceless blackshirts. For every naff image – down with spandex onesies – there's something else stark and gruesome. Horns burst, bloodily, through a human skull.

All this is real enough to get deep under your skin. Aberg has a fine sense of theatrical potency, be it the rip of plastic sheeting or the rasp of incantation. Orlando Gough's score – thrashed cymbals, throbbing bass, discordant choirs – pricks the hairs on your skin, Lee Curran's lighting flecks the stage with soft sickly neons and Ayse Tashkiran's choreography, juddering and stomping, sends shudders through the space.

What's so smart, though, is that the end isn't certain. Since Mephistophilis' deal is a con-trick, Faustus could still repent and save himself. That culminates, brilliantly, with an underage Helen of Troy – a slip in a slip. In Tashkiran's mesmeric sequence, Ryan flicks from light to dark. Jade Croot pushes him away, then jumps into his arms. He's paternal, then predatory. A hand through her hair becomes a hand on her mouth. She kicks, thrashes, then flees. For Faustus, it's the point of no return, damnation for definite.

Doctor Faustus runs at the Swan Theatre until 4 August.