Every drama has its moment of truth, and Mayerling’s comes when Crown Prince Rudolf’s teenage mistress Mary Vetsera picks up his gun, caresses its barrel, and points it at his head.

She looks at him with taut eroticism, and he looks back in bleakly aroused recognition that she’s squared the circle of sex and death. It is a terrifying scene that reveals our fascination with what seem like opposites only for Mary and Rudolf to conflate the two.

It’s a measure of Kenneth MacMillan’s greatness that his choreography can load a scene with such emotional static. It does, of course, require tip-top dance-actors, and at last night’s opening night Edward Watson and Mara Galeazzi came close, although neither danced with the clarity we know they possess.

Part of the reason is that it’s the Royal Ballet’s first performance after the long summer break, with Watson taking time to warm up, and Galeazzi rather relying on her admittedly lovely legs to see her through Act I.

The answer is to book tickets later in the run, by which time everyone will have warmed up and the stage glitches will have been resolved. It may not sound like much but tables and chairs were misaligned, meaning the dancers lost their concentration (and dropped character) as they negotiated their way. The ballet itself groans with detail (the letters, the pictures, the umpteen relations), which exacerbates the effect.

Mayerling tells the real-life story of Crown Prince Rudolf of Austria-Hungary who shot his mistress and himself at the Mayerling hunting lodge in 1889. Macmillan, who would have been 80 this year had he lived (he died backstage during a performance of the ballet in 1992), portrays Rudolf as an emotionally deprived man with a gun fetish and drug habit but little talent for kingship. He also confuses maternal love with sexual passion, making the Act I scene with his mother (Cindy Jourdain) especially gloomy.

There are also his new wife (Iohna Loots), a mistress‑turned-procuress (Sarah Lamb), and Hungarian separatists (including the dazzling Sergei Polunin) to contend with.

By Act III, Rudolf is set to snap, which Watson exactly catches. The only comfort comes from his other mistress (an under par Laura Morera), his faithful cab‑driver (the talented Steven McRae) and the understanding, alluring Mary. Her charms and his troubles are a dark combination.

In rep until 10 November.
Information: 020 7304 4000, www.roh.org.uk.