Kenneth MacMillan’s powerful ballet Mayerling ends with a pre-dawn secret burial in a monastery cemetery, the epilogue to the scandalous affair and double suicide of Crown Prince Rudolf of Austria-Hungary and his teenage mistress, Mary Vetsera, in 1889. The curtain falls to a faint funereal drum tap, the audience pin-drop silent.

It then rises again on the dancer who has played Rudolf, standing on a bare stage to receive the plaudits alone. Quite right. Mayerling is a ballet teeming with characters, several of them ballerina roles — including Mary, whom we have just seen dragged to her coffin in the gloom — but Rudolf is the phenomenal focus of this complex epic, one of the most demanding dramatic parts created for a male classical dancer.

On the opening night of the latest revival at Covent Garden, it was Jonathan Cope being showered with ovations. Not only, I thought, in admiration of a tremendous performance of physical stamina and psychological depth, but also in an outpouring of affection for his special place in the Royal Ballet today. At 41, he is the most senior of the company’s male principals, but still performing at strength against younger competition. He took premature retirement for a couple of years, but came back, and is also, in the “international” Royal Ballet, the only English male principal, entirely home-grown and home-trained. How different the make-up of the company was in 1978, when MacMillan was inspired to create Mayerling by an earlier native product, the superb dance actor David Wall.

Tall, handsome, elegant, with a clean, classical line, Cope has always been an immaculate dancer, but in his earlier years not the most impassioned. His remarkable partnership with Sylvie Guillem changed that, and the mature Cope portrays the emotionally tormented, drugged and diseased, sex- and gun-obsessed crown prince heading for destruction with a seething conviction that makes your hair stand on end.

As Mary, his suicidal soul mate, Tamara Rojo matches Cope’s performance with superlative dancing and erotic abandon. In the climactic scene in the hunting lodge, when the last of MacMillan’s brilliantly inventive, daring pas de deux could look death-defying if it weren’t actually precipitating their deaths, we are pinned to our seats in pity and terror.

The second of four casts in this run, Johan Kobborg and Alina Cojocaru, gave gripping performances too, though I feel Cope and Rojo have the edge. Mayerling is a big company ballet packed with big roles: Gemma Bond or Bethany Keating as Rudolf’s terrorised wife, Stephanie; Zen-aida Yanowsky or Genesia Rosato as the Empress Elisabeth; Jaimie Tapper or Laura Morera as Countess Larisch. All were admirable.

You learn to live with Mayerling’s weaker elements — too much bump and grind from the tavern whores, an ineffectual hunting scene, four seditious Hungarian officers who look rather ridiculous — because the high spots, those fantastic pas de deux, lay the characters bare and drive the plot with such force, as does the late John Lanchbery’s score arranged from Liszt, played splendidly under Graham Bond.

Miguel Angel Zotto and his popular, polished, world-renowned Argentinian company Tango Por Dos are back at the Peacock Theatre with their new show, Tango — Una Leyenda. There’s plenty of daring in the tango: as legs spear and scythe between partners’ thighs in the knitted duets, you might wonder whether they all wear chain-mail undies.

As in earlier productions, Zotto frames the dance numbers as a social history of the tango, from low dives to high-society clubs — this time interwoven with political themes and fantasy. Department-store mannequins that come to life are more successful than the goose-stepping policemen, and weird characters inspired by the lyrics of Horacio Ferrer for Astor Piazzolla’s new-tango tunes only make sense if you can follow the words. The costumes are glamorous, and Tito Egurza ’s split-level set with cityscape projections is marvellously versatile. The dancers and the band are all fine. Zotto shows off his slick footwork with several leggy ladies, and even does rock’n’roll (to Hound Dog). But by the end of a long evening, I felt I had seen and heard more than one tango too many.