FC Osijek is the club that was founded 1947. year. Throughout history, FC Osijek has managed to win the Croatian Cup winner's trophy in season 1998./99 years. The players of Osijek were close to winning new trophies severel times, for example winning another Croatian Cup when it was necessary to score a goal from the penalty spot, but after amiss the trophy went into other hands. In its history, FC Osijek recorded victories against big European clubs such as PSV, Slavia Prague, Brondby, Anderlecht. The aim of this master's thesis is to show and explain the defensive and attacking mechanisms of FC Osijek. In the season 2021./2022. FC Osijek finished in third place and qualified for the Conference league. In 36 games, 19 they won, 12 games without a winner and the 5 games left the field defeated. During 36 matches FC Osijek used formations 1-4-2-3-1, and 1-3-5-2 and from each formation they practiced defensive and attacking mechanisms in order to score a goal faster and more efficiently, or to prevent a goal in ther own net. The attack mechanisms in this paper refer to the phases of opening the game from the goalkeeper, to the phase of attacking the set defense where they used mechanisms through the middle or through the lateral positions, which are also explained through pictures. In themmechanism of defense, this paper explains defensive pressing, then the set defense in the opponent's half of the field, and the set defense in the second third of the field. Considering the number of goals conceded FC Osijek ended the season as the third most successful defense in the league. This data indicates that the defensive mechanisms functioned at a high level, while the attacking ones were not so effective, which should be improved in the future.