Fifa is to investigate Zinedine Zidane's dramatic sending-off during Sunday's World Cup final in Berlin. The Frenchman was dismissed in extra-time for a headbutt on Marco Materazzi which happened seconds after the Italian apparently insulted him. Materazzi has denied calling Zidane a "terrorist" or insulting his mother. Fifa will now launch an investigation into Zidane's conduct to enable it to clarify the circumstances surrounding the incident as exactly as possible. Zidane and Materazzi exchanged words with 10 minutes left of extra-time before Zidane lowered his head and rammed Materazzi in the chest, knocking him to the ground. Materazzi defended himself on Tuesday in the Italian newspaper La Gazetta dello Sport, when he said: "It was the kind of insult you will hear dozens of times and just slips out of the ground. I didn't call Zidane a terrorist and certainly didn't mention his mother." Zidane, who was born and grew up in Marseille, is the son of Algerian immigrants and has suffered taunts about his heritage throughout his football career. But Materazzi added: "I am ignorant, I don't even know what an Islamic terrorist is; my only terrorist is her," he said pointing to his 10-month-old daughter. "I did not bring up Zidane's mother; for me a mother is sacred." Materazzi and Zidane became involved in a verbal spat with 10 minutes to go in extra-time with France and Italy drawing 1-1 in the World Cup final. After Materazzi's insult Zidane shoved his head into the Italian's chest and was sent off, with Italy going on to win the match 5-3 on penalties. "I held his shirt, for only a few seconds," said Materazzi, who had scored Italy's equaliser after Zidane put France ahead from the penalty spot. "He turned towards me and scoffed at me, looking at me with super arrogance, up and down. He said 'if you really want my shirt, you can have it later.' It's true, I shot back with an insult."