Uefa has opened disciplinary proceedings against AC Milan midfielder Gennaro Gattuso following his conduct in Tuesday's match against Tottenham.
A magnificent 1-0 win for Spurs in the first leg of their UEFA Champions League tie was marred by ugly scenes after the game as Gattuso confronted Joe Jordan.
Having earlier clashed with the assistant Spurs coach on the touchline during the match, Gattuso pushed his head towards Jordan at the final whistle.
Several players from both sides became involved in a melee following the headbutt, although Gattuso later apologised for his actions.
"I lost control. There is no excuse for what I did. I take my responsibilities for that," he said.
"I was nervous. I didn't want to argue with players and I did it with him, but
I was wrong to do what I have done."
Gattuso is already suspended for the return leg at White Hart Lane after picking up a yellow card on Tuesday but could now face a lengthier ban.
Uefa's Control and Disciplinary Body will meet next Monday to discuss the case.
No further action will be taken, however, against Milan's Mathieu Flamini, whose two-footed challenge on Vedran Corluka was punished only by a yellow card.
Harry Redknapp has described the tackle as 'horrendous' but it does not appear possible that a tougher retrospective punishment could be imposed.
A Uefa spokesman said: "If he's been shown a card nothing can be done."