The 1998/99 season was a turning point for NK Osijek, a club that was on the brink of historical success. Under the guidance of coach Branimir Gajdas, the Bijelo-plavi showcased a game that thrilled fans and brought them numerous successes in the domestic league. During this period, Osijek earned a reputation as a team that could compete with the strongest, culminating in a historic qualification for the European League.

One of the key moments of that season was the victory against the then-champions, GNK Dinamo Zagreb. This win not only boosted the players' confidence but also created euphoria among the fans. The Gradski vrt stadium was packed, and the atmosphere was incredible, with supporters cheering on their heroes and believing in success until the final minutes of the match.

Osijek finished the season in a high third place, which was enough for qualification for the European League, and that moment was the crowning achievement of all the players' efforts and everyone who worked at the club. Players like Davor Šuker, who was in top form at the time, along with other talented individuals, were crucial to this success. Their dedication and hard work resulted in a historic achievement that would be remembered for a long time.

This success was not just the finale of one season; it was the beginning of something great for NK Osijek. The qualification for the European League opened doors to new opportunities, and the club gained an international reputation that attracted attention from other football circles. Fans could dream of new challenges on the European stage and how the Bijelo-plavi would represent their city and country at the highest level.

Osijek's journey to Europe was not just the result of good results, but a symbol of community strength, the unity of supporters, and the dedication of all who worked for the club. This historic season left an indelible mark in the hearts of Osijek fans and laid the foundation for future successes, with the Bijelo-plavi continuing to build their tradition as one of the most important clubs in Croatian football.