The material for Cecilia Bartoli's latest project, Opera Proibita, is not quite as sexy as her record company would have us imagine. Sadly, none of these arias is naughty enough to have ever been banned; the hook is that they all come from Italian oratorios of the first decade of the 1700s, when the Vatican had outlawed opera and the divas of the day had only the concert platform from which to send their admirers into a frenzy. This programme brought together Handel, Scarlatti and Caldara, the last two of which usually give very unsexy box-office indeed - but this was Bartoli, so the hall was packed.

This wasn't quite the concert of the CD. Bartoli had swapped Les Musiciens du Louvre for the Basel Chamber Orchestra, and lost out not one bit: indeed, the orchestral numbers were highlights in their own right, superbly vigorous, with oboe solos as eloquent as one could wish for. And she had dispensed with a conductor altogether, nominally taking over the direction herself, but wisely leaving most of it to the orchestral leader; for anyone whose idea of simultaneous singing and conducting rests on the memory of Jose Cura flapping like an albatross in front of a largely oblivious symphony orchestra, this would have been a refreshing antidote.

This collaborative spirit seemed to refocus Bartoli's usual self-consciousness. The fiery fusillades were still there, articulated so well as to pack a punch even though her voice is not huge. But she made even more of a point of drawing us in to the quieter moments, sidling over to the lead violinist for their intricate duet in Handel's Come Nembo, and daring anybody to breathe during Caldara's haunting Vanne Pentita.

Could it be that Bartoli is finally getting her mannerisms, physical and vocal, under control? Perhaps - but what's certain is that she provided the kind of star quality we rarely encounter in repertoire that is too often regarded as a consolation prize. By the end, even non-believers might have found themselves softening.