In November 1974, Lupu made his debut with the New York Philharmonic, performing Mozart's Piano Concerto No. 21 (K. 467) conducted by James Conlon. In 1975, Lupu debuted with the Concertgebouw Orchestra and gave the premiere of the André Tchaikowsky Piano Concerto, Op. 4 with the Royal Philharmonic Orchestra conducted by Uri Segal at the Royal Festival Hall. In 1976, Lupu recorded Brahms' 6 Klavierstücke (Op. 118) and 4 Klavierstücke (Op. 119), which was described by "Stereo Review" as "a glowing realization of what Brahms set down that leaves one at a loss for words and simply glad to have ears." In 1978, he gave his debut with the Berlin Philharmonic conducted by Herbert von Karajan at that year's Salzburg Festival. Reviewing a recital Lupu gave at Avery Fisher Hall in 1980, Andrew Porter of "The New Yorker" hailed Lupu as "a master of the most satisfying kind". By 1981 he had played with every major orchestra.