Pilić was already a star when tennis turned fully professional in 1968. When U.S. businessman Lamar Hunt backed a new professional tour called World Championship Tennis, the likes of Pilić, John Newcombe and Tony Roche were the first eight men's players signed — called the Handsome Eight.
Pilić won nine singles titles and reached a highest singles ranking of No. 6. He lost the French Open final to Ilje Nastase. His six doubles titles included the 1970 U.S. Open with Pierre Barthes against Newcombe and Rod Laver in a four-set final.
After his playing retirement in 1978, Pilić coached and won the Davis Cup as a non-playing captain with Boris Becker's Germany (1988, 1989, 1993), and Croatia (2005) and served as an adviser when Serbia won in 2010.