text: Before the Second World War, the city of Lille had two clubs at the top level; Olympique Lillois and SC Fives. Olympique Lillois were crowned domestic champions in 1932–33, the first in the history of the championship that was created in 1932, and were runners-up in 1935–36. They also earned a USFSA Football Championship title in 1914, the French football top division before the creation of the French Division 1, and went to the Coupe de France final in 1939. Their neighbours, SC Fives, ranked second in 1933–34. They also went to the Coupe de France final, being defeated by Girondins AS Port in 1941. Weakened by the war, the two clubs decided to merge in the autumn of 1944, on 23 September, giving birth to Stade Lillois, renamed Lille Olympique Sporting Club a few weeks later. On 25 November 1944, the club is officially registered under its new name.
  For its first season, the newborn club reached the 1945 Coupe de France final, with a squad composed of the best players of both merging teams, who are mostly natives of the Nord department. Next season, Lille won the double, beating Red Star in the 1946 Coupe de France Final and finishing at the first place of French Division 1 ahead of Saint-Étienne and Roubaix-Tourcoing. In 1947, Lille finished in the fourth place but came back to the Coupe de France final and retained the trophy, defeating Strasbourg. The club won the cup again in 1948 beating main rivals Lens, its third in a row, and were runners-up of the league the same year, behind Marseille that became the champions after a strong 1947–48 season finishing. They were also runners-up in 1948–49, 1949–50 and 1950–51. On 24 June 1951, an exhausted Lille reached the Latin Cup final and lost against Gre-No-Li's AC Milan after having played 250 minutes in the span of two days.