The absolute primary and most historic rival for F.C. Copenhagen is Brøndby IF, with their intense metropolitan clashes constituting the legendary New Firm derby of Danish football. This rivalry is fueled by geographic proximity, historical dominance, and contrasting club cultures, drawing massive media attention and fierce supporter engagement. While other regional clubs like FC Nordsjælland or FC Midtjylland present modern sporting challenges, the animosity and passion surrounding matches against Brøndby remain unmatched in Danish sports.