The Royal Ballet, Royal Opera House, London

Ballets Russes came to Paris in 1909 and kick-started the 20th century, now the Royal Ballet marks the event

Everyone, at some time, has played that game of imagining their lives in another era. No one ever chooses 1909 because of what came next, but it would have been great to have caught the buzz that greeted the Ballets Russes.

One hundred years on, almost to the day, it's hard to grasp its impact, first in Paris, then in London, then in almost every major city in Europe. This wasn't just an entertainment phenomenon. It was a tsunami of fashion, celebrity, art, music, design, exoticism and eroticism that burst through the floodgates of dour respectability to colour every aspect of civilised life. Just as the Sixties didn't really start swinging until 1967, the 20th century began in 1909.

The Royal Ballet – which itself was started in emulation of the ex-pat Russian troupe – is marking the centenary rather quietly. It could have put on a programme that underlined the modernism that so thrilled and scandalised early audiences. Instead, we have a triple bill book-ended by the prettiest and most hummable of ballets and a fairytale.

Granted, Les Sylphides isn't as old-fashioned as it looks. Its cast of white- gauze-clad girls may have silly little wings stuck in the small of their backs, but there the choreographer Mikhail Fokine's nod to history ends. These sylphs take their cue from the free-flowing movement ideas of Isadora Duncan: light as thistledown but womanly too: an Edwardian dream of femininity. So was it the conductor Barry Wordsworth's deathly slow speeds that made everyone look catatonic? Chopin can certainly be wistful, but some of these numbers almost ground to a halt – particularly irksome in the famous Prelude in A major whose theme in this treatment comes around 12 times.

Still, the drifting movements of the corps were beautifully matched, Lauren Cuthbertson and Laura Morera brought a welcome spark to their solos, and Yuhui Choe as the leading sylph was so miraculously weightless that she created a parallel illusion of transparency, like a petal or a leaf.

The Firebird – same choreographer, radically different style – is, by comparison, home territory for the Royal Ballet: not only is it constantly in the rep, but it tells a story, and these dancers can do that standing on their heads. I'd forgotten, though, how subtly and confidently they inhabit the Russian-ness in this story. Mara Galeazzi's scarlet-plumed creature has a fierce, dark allure, properly farouche; Thiago Soares, for all his appealing boyishness, is a Tsarevich with the weight of Russian history on his brow, and the crazy grotesques of the wizard Kostchei's kingdom (I love the monsters with washing-up-brush heads) tear into their climactic massed dance with the ferocity and commitment you once only got from the Kirov. The Royal Opera House orchestra, too, rise to the occasion, bringing a tear-duct pricking majesty to the final tableau set against the onion-domed roofs of Moscow. It's a magnificent revival.

The letdown comes with the new work, Sensorium, which attempts to create something fresh and contemporary from Ballets Russes elements. Debussy was used by Diaghilev, so, in principle his piano Préludes are fair game. But Alastair Marriott's bright, squeaky-clean responses – in what looks like a mass beach workout on the Riviera – profoundly miss the point of Colin Matthews's sensuous orchestrations. The shrouded mysteries of "Feuilles mortes" (Dead Leaves) and "Brouillards" (Mists) were met with sunlight, busy-ness, and too many prolonged flashes of leotard crotch. Do dancers shave? That's not a question I want to ponder, listening to Debussy.

In rep until 30 May (020-7304 4000)