Unless you had 80% to 20 possesion it was not an ilegal formation!, as for him scoring 3 goals in 4 mins, was he watching the game?, did he change his formation during the game?, he has probably played HARD TACKLING AND HARD ATTACKING because he was weaker!, I would counter his formation with 3-4-3 and play red arrows on all midfield and strikers, play HARD TACKLING, MIXED FOCUS PASSING, ATTACKING, CLOSE DOWN OWN HALF, MIXED PASSING STYLE, ZONAL MARKING, PLAY OFFSIDES.