During a recent referee course, former FIFA AR Dario Garcia, who is now a referee instructor in Argentina, described how they came out with the correct decision, although the referee did not see Zidane headbutting Materazzi.
Garcia was AR1 in the final of the 2006 FIFA World Cup played in Germany. "It was teamwork in a very complicated situation, which ended up with the correct decision. There were no protagonists; it was a team effort. The fourth official (Medina Cantalejo) saw the headbutt, he told me and I gave accurate information to Horacio (Elizondo). Based on that information, he sent off Zidane, who was one of the best players in the world at that time. If the communication within our referee team would had not worked, all our good work would had fallen through the cracks", said Dario Garcia.
Source: La Arena