A heavy police presence in and around Ewood Park on Wednesday night was not enough to quell the trouble, as matters boiled over following the Clarets' opening goal in their 2-0 win.
Two spectators ran onto the field immediately after Jack Cork's header, one of whom is in police custody on suspicion of assault after approaching a couple of visiting players.
A second fan was arrested for an unrelated incident, linked to a flare being launched from the stands towards the field which hit a nine-year-old child.
Three others were arrested inside the ground, meanwhile, all related to violent disorder.
Lancashire Police Chief Constable Terry Wood said: "I am truly appalled at the behaviour of these few, including the one believed to be from the Blackburn fans who encroached the pitch and thought it acceptable to assault a steward doing his job and two players there to partake in the match."