Cecilia Bartoli became famous by singing the music of Rossini better than anybody in living memory. She has played a significant role in making people take Rossini's operas more seriously. But in the past few years she has moved in a surprising direction, namely to Baroque music.

Now she makes Vivaldi's music sound as though it was written for her and her alone. Every passing detail of his florid vocal writing sounds perfect and new-minted. And a packed Bridgewater Hall sat increasingly enthralled through a substantial programme of little-known Baroque music, clamouring for more at the end. Such enthusiasm is extremely rare in British concert halls.

Perhaps it isn't surprising that this serious artist has made this musical switch with such rigour, taking in all that has been learned about Baroque singing styles and using instrumentalists who are in the forefront of historical performance techniques. Her band of seven players, Le Musiche Nove, at first sounded tiny in the cavernous hall. But very quickly they drew us into their world, making their larger gestures sound enormous and producing contrasts with sounds that were quiet almost beyond belief. These musicians, gloriously led by the violinist Daniela Nuzzoli, are part of the astonishing recent rise in historical playing in Italy, which is fast becoming the country that leads the world in Baroque music.

Bartoli presents Vivaldi with infectious zest, brings life to all the details, makes everything sound a masterpiece. Above all, there is never the slightest hint of compromise. Everything is pure musical delight, flawlessly performed. Artistry on this level is very rare indeed.