He is best remembered in Romania for being the national team's coach at the 1970 World Cup and for inventing the "temporizare" ("delaying") tactics in which the team keeps the possession of the ball inside its own half and the players are using many short passes from one side to another of the field in order to disrupt the opponents patience when they go out of their field to make pressing, this is also considered an early form of tiki-taka, with such tactics he managed to qualify Romania to a World Cup after more than 30 years and register a win against Czechoslovakia.

[2][3][4][5] Angelo Niculescu was born on 1 October 1921 in Craiova, Romania and he started playing football in 1937 at age 15 in Divizia B at local club Rovine Grivița.

Niculescu started coaching in 1952 at Dinamo București's junior center, after one year moving to be the head coach of the senior squad which he helped win the first Divizia A title in the clubs history in 1955, also reaching the 1954 Cupa României final which was lost by Dinamo with 2–0 in front of Metalul Reșița and led the team in the first European match of a Romanian team in the 1956–57 European Cup in the 3–1 victory against Galatasaray, helping The Red Dogs go to the next phase of the competition where they were eliminated by CDNA Sofia.

[20] He was named coach of Romania's national team in 1967, making his debut in a 1–0 home loss in front of Italy at the Euro 1968 qualifiers.

[6][7][9][10][11][12][22] He also guided the national team at the 1972 Euro qualifiers where they earned the first position of a group composed of Czechoslovakia, Wales and Finland, thus managing to reach the quarter-finals where Romania was defeated by Hungary, who advanced to the final tournament.

[25] He is known in Romania for inventing the "temporizare" ("delaying") tactics in which the team keeps the possession of the ball inside its own half and the players are using many short passes from one side to another of the field in order to disrupt the opponents patience when they go out of their field to make pressing, this is also considered an early form of tiki-taka, with such tactics he managed to qualify Romania to a World Cup after more than 30 years and register a win against Czechoslovakia.