The Royal Opera's new production of Don Giovanni opened only a month ago, but the changes wrought on it by a complete change of cast and conductor are so radical that it almost qualifies as a revival. Crucially, the production is now peopled with real characters rather than ciphers, performers who offer genuine insights into the roles they are playing.

The transformation is multi-faceted, but the greatest gains are musical, and it is the performances that now make the show well worth seeing, or at least hearing. It all begins in the pit. Charles Mackerras's reading of the score is everything Colin Davis's before him was not: alive, transparent, yoked inseparably to the drama. The orchestral playing has pungency and point; it's the best kind of modern-instrument Mozart. The difference is not just that Mackerras prefers faster tempi - the Champagne Aria is taken at such a lick that the words almost trip over themselves - but that he provides his superlative cast with a platform on which they can deliver theatrically compelling and integrated performances.

At the heart of it all is Simon Keenlyside in the title role. Though he wears the same lank Meatloaf wig, his characterisation is worlds away from Bryn Terfel's, which suggested nothing more than a bit of a lad on the lookout for some slap and tickle. Keenlyside's Giovanni is a dangerous, proud predator in whom violence always simmers below the surface. He can switch from genteel seductiveness to physical threat in a moment, registering all the gradations in his wonderfully vital and well-focused singing. He is helped by having a perfect foil in Ildebrando d'Arcangelo's Leporello; the repartee bounces between them, so that our perspective on their relationship constantly changes.

The new Anna is the American soprano Christine Goerke, feisty, moving and vocally hugely imposing. Elvira is Ana Maria Martinez, who wins our sympathies without a trace of the overplayed madness that afflicted the character before. John Mark Ainsley's Ottavio also has a bad wig to contend with, but he creates such a powerful presence and sings his arias with such stylish directness it hardly matters.

There's also a sonorous Commendatore from Andrea Silvestrelli, a perky Zerlina from Natalie Christie, and a highly promising Masetto from the young Darren Jeffrey. Altogether a fabulous evening musically.

· Until February 28. Box office: 020 7304 4000.