1954 saw her make her debut at the Salzburg Festival, and she appeared in Rolf Liebermann's "Schule der Frauen", three years later. From 1954, she became a guest singer at the Vienna State Opera. New York City audiences had their first chance to hear the soprano's fine voice in 1960, when she sang there in "Der Rosenkavalier". Her performance prompted Lotte Lehmann to call her 'the best Sophie in the world'. Herbert von Karajan chose her to appear alongside Elisabeth Schwarzkopf and Sena Jurinac for the filmed performance of "Der Rosenkavalier" at the Salzburg Festival.