He immediately emigrated to Italy and signed with Inter Milan (where he was to remain until 1968), winning three Serie A titles and two European Cups during his stay with the club, where he used a 5–3–2 formation, and modified a tactic known as the "Verrou" (door bolt) – used by Karl Rappan – to include larger flexibility for counter-attacks; thus, the "Catenaccio" system was born. The side was later nicknamed "Grande Inter", due to the club's successes under Herrera's eight–year spell, which saw the team win back–to–back European Cup titles in 1964 and 1965, as well as three Serie A titles, and two Intercontinental Cup titles. During this time he was also coaching Spain (between 1959 and 1962) and Italy (1966–67).