Following his U.S. debut, Oscar and his quartet toured in the illustrious company of the Dizzy Gillespie Quintet, the Stan Getz Quartet, the Lalo Schifrin Trio and the Laurindo de Almeida Quartet before he returned to Brazil to resume a busy schedule as an arranger and producer. In 1971 he made Los Angeles his permanent home, joining Sergio Mendes' Brazil '66 group as the featured guitarist, music director and vocal coach. When he left the group in 1981, he had recorded more than 15 albums with Mendes, had co-producer many, and had appeared in concert in dozens of the world's major cities.
Word of his arranging and guitar expertise spread quickly among the close-knit community of studio musicians and producers in Los Angeles, resulting in an avalanche of opportunities to arrange and produce for other artists and lend his guitar style to countless studio sessions. Among the many highlights of his tenure in the U.S. as the resident dean of Brazilian sounds have been collaborations with Antonio Carlos Jobim, Elis Regina, Flora Purim, Yo-Yo Ma, Joe Henderson, Michael Jackson, Barbara Streisand, Stevie Wonder, Stan Getz, Eliane Elias, João Gilberto, Lee Ritenour, Airto Moreira, Edu Lobo, Toots Thielemans, Paul Winter, Diane Schuur, Herbie Hancock, Ella Fitzgerald, Ottmar Liebert, Lisa Ono and countless other Brazilian, jazz and pop music stars.