After the game, Sir Alex Ferguson called for an FA inquiry, but Wenger would only say: "Why are we always the devils playing against the angels."
Tempers boiled over at Old Trafford after Vieira's red card following a clash with Van Nistelrooy. The pair were later involved in a tunnel bust-up.
The dismissal was the French midfielder's eighth for Arsenal and the 52nd during Wenger's seven-year reign. Hill-Wood added: "I have said before that our disciplinary record is not good and it does concern me."