Tuhia he haere tonu mo tenei whitianga - I nga tau whakamutunga o te 1950 i hangaia e Varviso etahi manuhiri manuhiri rongonui, tae atu ki te Deutsche Oper Berlin (1958), Paris Opera (1958), me te San Francisco Opera (1959), ko te mea whakamutunga ko tana mahi tuatahi ki te whakahaere i te United States. I te tau 1958 i whakahaerehia e ia te whakaaturanga tuatahi o te ao o Heinrich Sutermeister "" i te Brussels World Fair
He aha? I te 10 o Oketopa 1961 ka hoki ia ki San Francisco ki te whakahaere i te whakaaturanga tuatahi o te United States o Britten's "A Midsummer Night's Dream". I whakahaerehia e ia a "The Marriage of Figaro" mo tana mahi tuatahi i te Glyndebourne Festival i te tau 1962 whai muri i te mahinga o "Der Rosenkavalier" mo tana timatanga me Covent Garden i tera tau. He maha nga wa i hoki mai ai ia ki te Royal Opera puta noa i te toenga o tana mahi, e whakahaere ana i te raarangi whanui mai i nga mahi paerewa a Mozart, Puccini, Strauss, me Wagner, ki nga opera iti ake e mahia ana penei i a Debussy's "Pelléas et Mélisande".