 He made his Metropolitan Opera debut in 1988 conducting Handel 's opera Giulio Cesare , the same year he made his debut at the Salzburg Festival with Handel 's Messiah . He conducted Opera Australia and Michael Chance in Handel 's Rinaldo at the Sydney Opera House in 2005 . He also played William Babell 's virtuoso harpsichord transcriptions with some of the arias ( which Babell claimed were of Handel 's actual improvisations ) . 
