The Royal Opera's new production of Rossini's La Donna del Lago is a strangely divided effort. It contains some of the most spectacular singing to be heard at Covent Garden for a while and vindicates an opera some consider uneven. Its opening night, meanwhile, also offered – in the shape of tenor Michael Spyres, replacing indisposed Colin Lee as Rodrigo – one of those electrifying short-notice debuts that can make a career. The downside is a fussy staging by John Fulljames that gets in the way.

Based on Walter Scott's The Lady of the Lake and first performed in 1819, the opera is a product of the Romantic obsession with Renaissance Scotland as a place of emotional and political extremes. Fulljames reinvents two minor characters, Serano (Robin Leggate) and Albina (Justina Gringyte), as Scott and Rossini themselves, and presents them poring over historical material at an exhibition. Joyce DiDonato's Elena is a literal museum piece, taken from a display case at the start of the evening and returned to it at the end. A sentimental 19th-century landscape mural, meanwhile, opens to reveal assorted highlanders going in for such things as disembowelling deer. Fulljames undercuts Rossini's royalism by referencing the suppression of the 1745 Rebellion; a fair point, though it only adds, I'm afraid, to the growing confusion of periods and allusions.

Musically, though, it's superlative. DiDonato, all ecstatic coloratura and floated high notes, is mesmerising opposite Juan Diego Flórez's thrilling King, and Daniela Barcellona is moodily introspective as her lover Malcom. Then there's Spyres, whose mix of baritonal lower registers with a Flórez-like ease and flexibility at the top is sensational and unique. It's nicely conducted by Michele Mariotti, too. It's unmissable, despite the staging.

* Screened live in cinemas in the UK and internationally on 27 May.

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