1945 - 1991
The Yugoslav Era
After the end of the war, football in Ljubljana and Slovenia was revitalized. In 1945, SK Ljubljana participated in the first post-war Yugoslav championship and later that year merged with two other clubs (ŠD Tabor and ŠD Udarnik). This merger resulted in the formation of a new major club, NK Enotnost, which was renamed NK Odred three years later. In 1953, Odred earned its first promotion to the Yugoslav First League, although it remained there for only one season. In 1961, the club briefly changed its name to ND Triglav, but midway through the season, it was renamed to Akademski nogometni klub Olimpija. In the 1964/65 season, Olimpija secured promotion to the Yugoslav First League with a victory over Borac Banja Luka in front of 15,000 spectators. The club remained in the top league for an impressive 19 years.
Even during this period, the derbies against NK Maribor were the most anticipated and well-attended matches. On April 6, 1964, an incredible 19,994 spectators gathered at the Bežigrad Stadium – a record attendance for any football match in Slovenia to this day. Olimpija thrived during this era and reached the peak of its success in 1970 by advancing to the Yugoslav Cup final. Despite a valiant effort, the team narrowly lost to Crvena Zvezda (2–2 and 0–1 after extra time in the 120th minute). However, this performance earned Olimpija a spot in the European Cup Winners’ Cup competition.
Between 1966 and 1984, Olimpija reached the semifinals of the Yugoslav Cup twice and qualified for the Inter-Cities Fairs Cup (the predecessor of the UEFA Cup) on two occasions. However, in the Yugoslav First League, the club generally finished in the lower half of the table. In 1984, Olimpija was relegated from the First League, marking a significant downturn for the club. The struggles continued as the team also dropped out of the Second League. Despite these setbacks, the situation stabilized in the latter half of the season, and Olimpija finished in third place. The following season saw an incredible comeback, as the team dominated the Second Federal League with 20 wins, 6 draws, no losses, and an impressive goal difference of 64:4, securing their return to the Second League. On September 4, 1988, during a match against Dinamo Vinkovci, the first signs of an organized fan group, the Green Dragons, appeared in the stands. The group was officially established on October 2, 1988, marking the beginning of organized fan support at football matches in Ljubljana. In 1989, during the inaugural season of the unified Second League, Olimpija convincingly won the championship, earning a well-deserved return to the Yugoslav First League.
Olimpija’s return to the Yugoslav First League ignited football euphoria at a time when political tensions in the former Yugoslavia were running high. The pinnacle of this excitement came on November 11, 1989, when Olimpija defeated Crvena Zvezda in a dramatic penalty shootout. However, the following season, which was also the last in the Yugoslav league, was less successful. Olimpija finished in 14th place, losing many key players during the campaign. Political unrest and the looming war further dampened the atmosphere, resulting in declining attendance at matches. Olimpija played its final match in the Yugoslav First League on June 17, 1990, against Dinamo Zagreb.