 During the years, as the two teams became more and more successful, they gained large supporter bases.The confrontations between the clubs and their fans became commonplace and often resulted in tense encounters on the pitch and hooligan clashes between the fans off the pitch.The hostility reached its climax on 19 June 1985 during the Bulgarian Cup final held at Vasil Levski National Stadium when, after many disputable referee decisions, both teams demonstrated poor sportsmanship which resulted in regular fights between them on the pitch.