Rütgers began her training with Hermann Weißenborn in Berlin,[1] then studied briefly in Italy and then with Hilde Wesselmann at the Folkwangschule in Essen.
Between 1963 and 1965 she performed at the Salzburg Festival, the part of Die Vertraute (Her confidante) in a production of Elektra by Richard Strauss, conducted by Herbert von Karajan, alongside Astrid Varnay in the title role, and Martha Mödl, Hildegard Hillebrecht, James King and Eberhard Waechter in leading parts.
[2][3] The production of Mozart's Die Zauberflöte at the Salzburg Festival, with Rütgers as the Third Boy, was filmed and released as a made-for-television-movie in 1964.
[4] She appeared alongside Walter Kreppel as Sarastro, Roberta Peters as the Queen of the Night, Pilar Lorengar and Waldemar Kmentt as Pamina and Tamino, and Renate Holm and Walter Berry as Papagena and Papageno, in the production staged by Otto Schenk and conducted by Istvan Kertesz.
3 and Te Deum with the choir Philharmonischer Chor Schwäbisch Gmünd, featuring Günter Reich, Kari Løvaas and Kurt Huber with the Nuremberg Symphony Orchestra.