Zinedine Zidane's [Images] head-butt on Italy's [Images] Marco Materazzi in the World Cup final might cost him the tournament's Golden Ball award, FIFA president Sepp Blatter hinted in an interview published on Wednesday.

World football's ruling body opened a disciplinary investigation on Tuesday into the circumstances surrounding the incident in Sunday's final.

"FIFA's executive committee has the right and duty to intervene when it sees behaviour that is contrary to sports ethics," he was quoted as saying in an interview in Rome's La Repubblica newspaper.

Asked if Zidane risked being stripped of the award for the World Cup's best player, Blatter said: "Before we make any decision we have to await the outcome of the investigation.

"Being presumed innocent until proven otherwise is sacred principle."

But he added: "Seeing him behave this way really, really hurt me."

Playing the last match of a great career, the French midfielder drove his head into Materazzi's chest in the second period of extra time in Berlin after exchanging comments with Materazzi. He was shown a straight red card by the referee.

FIFA's Golden Ball award was decided by media at the World Cup.