Helenio Herrera Gavilán (Spanish pronunciation: [eˈlenjo eˈreɾa ɣaβiˈlan]; 10 April 1910 – 9 November 1997) was an Argentine football player and manager.

[5] Playing as a central defender, in 1932 the 22-year-old Herrera earned a transfer from RC Casablanca to mainland France, to CASG in Paris.

His managing career, which coincided with the early beginnings of UEFA competitions, had a marked effect on the game's tactical development.

[6] 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.

He won the Coppa Italia in his first season, but relations with club president Alvaro Marchini had already soured over the tragic death of his centre-forward Giuliano Taccola in the team dressing room at an away game against Cagliari.

He pioneered the use of psychological motivating skills – his pep-talk phrases are still quoted today, e.g. "he who doesn't give it all, gives nothing", "with ten our team plays better than with eleven" (after his team had to face the second half of a game with only ten players on the field) and "Class + Preparation + Intelligence + Athleticism = Championships".

"[citation needed] He introduced the ritiro, a pre-match remote country hotel retreat that started with the collection of players on Thursday to prepare for a Sunday game.

While defensive in nature, his understanding of the Catenaccio was slightly different from that practised by other Italian teams and the original Verrou, as he often used the full backs (particularly Giacinto Facchetti) as half backs (defensively supported by the libero) to launch faster counter-attacks, a staple of Italian tactics – yet, he never denied the heart of his team relied on defence.

[9][10] Herrera's standard formation at Inter was the 5–3–2 system, which almost always included a sweeper (usually the team's captain, Armando Picchi), as well as four man-marking defenders.

[13] This was made possible due to Herrera's use of very quick and energetic, attacking full-backs, such as Giacinto Facchetti, and Tarcisio Burgnich, who would often detach themselves from the back-line, and catch their opponents by surprise with their overlapping runs.

[13] Furthermore, the team's main creative force, Spanish deep-lying playmaker Luis Suárez, played a fundamental part in Inter's success during this period, due to his outstanding work-rate, technical skills, vision and passing range; these attributes enabled him to aid the team to win back possession, and subsequently launch quick attacks with accurate long balls out to the on-running full-backs, who would often go on either to score or assist the strikers.

Celtic won the game 2–1 after coming back from a seventh-minute Mazzola penalty, with many pundits claiming this was a "victory for football" against the defensively-destructive Catenaccio.