Rubén Oswaldo Díaz (1946–2018), widely known by the nickname "Panadero," was an Argentine professional footballer and coach who played primarily as a left-back. He is recognized for his significant contributions to Racing Club in Argentina and Atlético Madrid in Spain during the 1960s and 1970s.
Díaz began his professional career at Racing Club, where he was a key member of the squad known as "El Equipo de José." During this period, the club achieved several major titles, including the Argentine Primera División in 1966, the Copa Libertadores in 1967, and the Intercontinental Cup in 1967, where Racing defeated Celtic FC to become the first Argentine club to win the world title.
In 1973, Díaz moved to Spain to join Atlético Madrid. During his tenure there, he won the Intercontinental Cup in 1974, a Copa del Generalísimo (now Copa del Rey) in 1976, and the Spanish La Liga title in the 1976–1977 season. He made 84 league appearances for the Spanish club before returning to Argentina to finish his playing career at Racing Club.
Following his retirement from active play, Díaz transitioned into coaching. He became a prominent assistant manager, most notably maintaining a long-term professional partnership with Alfio Basile. In this role, he served on the coaching staff for the Argentina national team during the 1994 FIFA World Cup and several Copa América tournaments, as well as at various clubs including Boca Juniors and Atlético Madrid.
Díaz died on January 16, 2018, in Buenos Aires, following complications from a surgical procedure. He remains a highly regarded figure in the histories of both Racing Club and Atlético Madrid.
