A new chatelaine at Glyndebourne

L'incoronazione di Poppea/Eugene Onegin Glyndebourne, East Sussex; until 11 July

Roméo et Juliette/A Midsummer Night's Dream Theatre Royal, Nottingham, Thurs-Sat; then on tour

Not since the soubrette Audrey Mildmay, for whom its original opera house was built in 1934 by her adoring husband John Christie, can one woman have held Glyndebourne in such thrall. Young American soprano Danielle de Niese, who wowed the cognoscenti as Handel's Cleopatra these last two summers, is doing so again in the title role of Monteverdi's L'incoronazione di Poppea, bringing much-needed lustre to the dreariest of stagings.

At the final curtain, she holds the stage alone in statuesque triumph as even the Emperor Nero backs off into the wings. Both cast and drooling audience seem in awe of the 28-year-old Californian, born in Australia of Dutch-Sri Lankan parentage, but only the most cloth-eared cynic would say it's because she's walking out with Glyndebourne's own Nero, its hereditary boss Gus Christie. The contented butt of Citizen Kane-type jokes about perhaps becoming chatelaine of the East Sussex manse, de Niese is undoubtedly an operatic force to be reckoned with.

Poppea is not as exotic a showcase for her charms as was David McVicar's all-singing, all-dancing Cleopatra, but she sings the taxing role with an accuracy beyond her years, endowing it with as much charm as a go-getting Roman harpy can muster. Clad much of the time in no more than a negligee, de Niese makes a decidedly odd couple with Alice Coote's dour if strongly-sung Nerone, apparently bisexual in Robert Carsen's perverse modern-dress production. All red velvet and kinky cross-dressing, it makes nothing of the imperial politics at stake.

From the prologue, and a commotion in the stalls over an apparently double-booked seat, Amy Freston's Amore runs the show, capering through every scene in the fetishistic red velvet that fills the stage in industrial scale swaths. Paolo Battaglia's noble Seneca is about the only character who does not die in the bath he orders for that purpose; the next three scenes, covering homoerotic murder to naked (female - phew) foam antics, are all staged in a tub wheeled laboriously around.

When not obscured by panto dames, there are polished performances from Tamara Mumford's Ottavia, Christophe Dumaux's Ottone and Marie Arnet's Drusilla. But the real stars, apart from de Niese, are Emmanuelle Haïm and her Orchestra of the Age of Enlightenment, who duck and dive through the intricate score with sleek, if paradoxical, period-instrument modernity.

The LPO takes similar laurels in a much better Glyndebourne bet this season, its revival of Graham Vick's 1994 Eugene Onegin, which music director Vladimir Jurowski conducts with authentically Russian passion, guiding a talented young cast through a truly noble version of Tchaikovsky's masterwork. Latvian soprano Maija Kovalevska makes a promising house debut as Tatyana, with Slovakian baritone Ales Jenis as a suave if understated Onegin and, above all, Italian tenor Massimo Giordano is a thrillingly ardent Lensky. Not to be missed.

Nor is Opera North's triptych of Shakespeare operas, which hits the road this week with a tuneful Roméo et Juliette and a dazzling A Midsummer Night's Dream in repertory with the powerful Macbeth reviewed here last month. The fine house orchestra plays its collective heart out for Martin André in Gounod's version of the Verona romance, which just about survives a fussy staging by John Fulljames, with two gifted young singers, Leonardo Capalbo and Bernarda Bobro, gracing the title roles. The chorus is on top form, but spoils things by giving away the ending in the opening scene. At least that means you can avert your eyes from the weird, almost wilfully anti-Bardic surtitles (viz 'Separating is such sweet sadness').

If you can make only one of these three operas, as they visit Nottingham, Newcastle, Manchester and Woking, catch Martin Duncan's glittering version of Britten's Dream. Amid sparkling set and costume designs by Johan Engels and Ashley Martin-Davies, a superb ensemble cast brings out all the wit and wisdom, plus every nuance of Britten's shimmering score, with rare relish and good taste. Henry Waddington's Bottom adds a well-judged pinch of poignancy as Stuart Stratford conducts impeccably.