Mark Clattenburg once admitted that he was so scared of Roy Keane that he changed his mind about a decision. The former Manchester United midfielder struck fear into referees and opposition players with his intimidating demeanour.
Whether he was locking horns with Patrick Vieira, barking orders at his teammates or contending the referee's every call, Keane wore his heart on his sleeve.
While he was a world-class player in his own right, the Irishman's incredible passion and determination to win often pushed his side over the line.
During his career, he was so unnerving for match officials that he once convinced a former Premier League referee to change his decision in United's favour.
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