In Toronto, as general director of the Canadian Opera Company for 12 years, Mansouri directed 30 new productions, 12 of them Canadian premieres, including Wozzeck, Lulu, Death in Venice, Die Meistersinger von Nürnberg and Thomas's Hamlet (featuring the only Ophelia ever sung on stage by Dame Joan Sutherland). In 1983, under his direction, the Canadian Opera Company introduced "supertitles"-English translations of foreign libretti projected above the proscenium during performances. Mansouri's innovation spread rapidly to opera houses throughout North America and Europe and is now used for every production of the Fall Season at San Francisco Opera.