Video: Five famous headbutts in football
Roy O'Donovan's headbutt of Phoenix player Manny Muscat marred Central Coast's 3-1 A-League win in Gosford on Thursday night. The blatant act of thuggery was one of the more severe headbutts seen in football, but there have been much more famous ones.
Here's four famous footballing headbutts, plus another look at O'Donovan's moment of madness.
No surprises about this one, undoubtedly the most infamous headbutt in football.
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In the 2006 World Cup final, the last international of the great Frenchman's career, Zinedine Zidane lost the plot, headbutting Italy defender Marco Materazzi in the chest.
There has been much debate about what Materazzi actually said to ignite Zidane, but the upshot is the French star was sent off, and his team went on to lose the final on penalties.
It was the worst of ways for a great career to end.
Argentina's Ariel Ortega saw red in the 1998 World Cup quarterfinal against the Netherlands, having lashed out at Dutch keeper Edwin van der Sar after he accused Ortega of diving in an attempt to win a penalty.
It wasn't the worst headbutt you will see, but a headbutt is a headbutt and the playmaker was dismissed.
Dennis Bergkamp scored soon after to send the Dutch into the semifinals, and Ortega and Argentina home.
This was was not your normal headbutt, given it was Beninese referee Coffi Codjia on the receiving end - and then he failed to actually send the culprit off!
Codjia was later suspended himself, for failing to send Algerian goalkeeper Faouzi Chaouchi off for the headbutt, which occurred in the 2010 African Cup of Nations clash between Egypt and Algeria.
Not happy with Codjia's decision to award a penalty, Faouzi Chaouchi grabbed the referee by the collar and promptly landed a butt on him, albeit one on the lower end of the scale.
Chaouchi was only awarded a yellow card for his troubles, a decision Codjia would have regretted as he was taken off the short list to officiate at the World Cup that year.
The 2006 World Cup match between Portugal and the Netherlands was famous for a staggering 16 cards being handed out by the referee, in what Goal.com dubbed the 'Battle of Nuremberg'.
Funny, then, that Portugal great Luis Figo managed to stay on the pitch despite clearly raising his head to Dutchman Mark van Bommel.
Despite calls for retrospective punishment, Figo was free to play the next match against England and Portugal went all the way to the semifinals.
Central Coast player Roy O'Donovan lined up Wellington Phoenix defender Manny Muscat in the 59th minute of their A-League match on Thursday night with a vicious headbutt, and essentially escaped punishment because referee Kris Griffiths-Jones missed it.
The two players were involved in a scrap for the ball - and Muscat may not have been squeaky clean himself in the scuffle as replays showed he may have made contact with his elbow to O'Donovan's face - but after play had moved on and the pair were running back, O'Donovan used decent force to blatantly headbutt the Phoenix player.
Phoenix captain Andrew Durante and Muscat were furious, yet Griffiths-Jones merely produced a yellow card for O'Donovan for his part in the scuffle, and to rub salt into the wounds Durante got one, too.
All O'Donovan got for his act of thuggery, apart from a booking, was a badly cut eye and an ovation from the home crowd when he came off toward the end of the match.