The worry with Edward Watson dancing Crown Prince Rudolf in Kenneth MacMillan's Mayerling is whether he has the strength. Rudolf is easily the most demanding male lead in all classical ballet, a truly marathon role, with the doomed prince dancing seven massive duets with six different ballerinas. Then there's the acting, three hours of it, including his goading, and raping, his hapless bride, Princess Stephanie.

Rudolf must show us emotional isolation, drug-addled depravity and shudders of syphilis-induced pain. We also want strong lifts and seamless duets. The best male dancers have their work cut out with Rudolf, and although Watson is a charismatic soloist with a fine line in weirdos, he's never had the partnering skills the role requires.

Unexpectedly, then, his debut at Monday's matinee was hugely assured. On the physical side, Watson has clearly been in the gym, while his partnering is vastly improved. Credit in spades to his coach.

Even better is Watson's acting, which draws out Rudolf 's troubled character, from sadistic husband to political innocent and a tearing, clutching, guntoting lover. The scene with his mother is grim indeed, as is the abuse of his wife, although his surprise at meeting Mary, and her mistaking his Hamlet for a Romeo, snags all prizes.

Also unexpected was the matinee cast being better than the evening one (this is rare). Watson's acting was superior to anything Carlos Acosta could produce (although Acosta is the better dancer), Iohna Loots was better as his wife, Cindy Jourdain was, amazingly, better than Zenaida Yanowsky as his mother, Sarah Lamb was the better Marie Larisch (an ex-mistress), Steven McRae was (just about) the better Bratfisch, and Laura Morera's Mitzi Caspar was streets ahead of the normally untouchable Marianela Nunez.

The only disappointment were the Marys. Both Mara Galeazzi (matinee) and Leanne Benjamin (evening) lacked the lush vanity and the fatal sexual fascination the role requires.

In rep until 7 May (020 7304 4000).