Preston North End have been fined £10,000 by the Football Association and warned about their future behaviour following a pitch invasion at Deepdale at the end of last season.
Supporters ran onto the field of play at full time after securing a 4-0 aggregate victory over Chesterfield in the League One playoff semi-final.
Chesterfield skipper Ian Evatt claimed at the time that he was "punched, kicked and spat on several times" in the immediate aftermath of the game, which later led to one arrest.
An independent regulatory commission has now found Preston guilty of breaching FA rule E20 for a failure to protect the safety of both sets of players.
In a written response to the FA, a Preston official stated: "Supporters were in celebratory mood because of their team had won they would use any means to enter the pitch.
"Other than the reported assault on Mr Evatt, no other assaults or disorder occurred in the stadium and there were no injuries as a result of the pitch invasion."
North End have been warned to put in place additional measures in future to avoid a repeat scenario.