Matilde Di Shabran, Royal Opera House, London

The peasants, if not revolting, were certainly agitated as they crept through the auditorium. The Royal Opera Orchestra, under the pointed baton of Carlo Rizzi, had already set the tone of jaunty militarism, the trombones and side drum spurring on the inevitable Rossini crescendos. One of his great rarities – Matilde di Shabran – had arrived from Pesaro, his home town, in probably less time that it takes its anti-hero, the dastardly Carradino (Iron Heart), to appear.

In the most protracted set-up imaginable we are warned to be afraid, be very afraid. The misogynistic despot knows no mercy, his fearful brutality makes it dangerous even to breathe. So when he finally descends the spiralling staircases of Sergio Tramonti's design – cue round of applause – it comes as something of a surprise that he is none other than the pretty, pint-sized Juan Diego Florez neatly tucked into a leather doublet and hose. Well, I suppose if terror can be measured as a succession of prodigious vocal runs, then he's pretty scary. But then again, the joke of this immensely long, one-joke opera is whether or not the pugnacious puppy will be brought to heel by the glamorous Matilde di Shabran of the title. And, if so, how many will die in the process? Four hours later...

Still, now we've heard and seen it once and, yes, there are some showy numbers for a top-notch cast to get its teeth into. There's a trio that becomes a quintet where Rossini gives us a flash of what he could do when he put his heart into it – and there are the seething, scatological ensembles. There's a marvellous role – Isidoro, a poet – for a great Italian buffo baritone. Alfonso Antoniozzi is certainly not that, but he raised a laugh or two. Marco Vinco, on the other hand, was just what the doctor ordered. As Corradino's physician, he turned in a commanding, verbally dextrous display of the Rossini style.

Not so Vesselina Kasarova (Edoardo). Her weirdly dislocated singing managed to swallow 50 per cent of the notes in a series of odd glottal catches down in her chest register. Awful.

And Florez? For all his charm, this is not an especially grateful role for him. Matilde di Shabran – in the form of Aleksandra Kurzak – not only tames but upstages him. In the final 20 minutes, all he can do is stay silent and look on in amazement as she dazzles with her jubilant, ear-popping finale. And to think he let her into the castle.

In rep to 11 November (020-7304 4000). This performance is broadcast on BBC Radio 3 on Saturday 22 November