There's been a lot of comment on Zidane's head butt on Materazzi during the World Cup Final.

While I don't agree with it, I completely understand it, and it is completely in character with Zidane- or any other great sporting champion. Because sporting greatness in virtually any sport requires having a ruthless and mean streak. Sometimes the streak gets a little out of hand. It comes with the territory.

Think of Michael Jordan's legendary competitiveness. Lance Armstrong's obessive focus. Michael Schumacher's driving style and tactics. Pelé breaking the legs of Kiesman and Procópio. Or of Muhammad Ali, who deliberately prolonged his pounding of Ernie Terrell in 1967, and taunted Floyd Patterson and Joe Frazier, destroying both of them mentally.

The fact is, in sport, to be a great champion you need to have that killer instinct. Off the field you can be the nicest guy in the world- but when you get on the field you have to want to win so badly that you will destroy anyone who gets in your way. I personally must confess my best performances came when I had psyched myself to the point of hating my opponent.

At the same time, of course, you must control your emotions, they must not control you. Your emotions are your slaves, not your masters. So I don't agree with what Zidane did, but I completely understand why he did it, and his greatness and legacy as an athlete is not tarnished in my eyes.

On a lighter note, this made me laugh: