Bosnia-Herzegovina lost the match. Their fans behaved in the literal sense of the word "fans" - short, of course, for "fanatical". O'Leary was threatened, he feared not only for his safety but his family's back in New Zealand.
It was an experience that, at the time, was testing. But it has clearly become something that has contributed to his character.
And he is now in a position to share his experiences - good, bad and ugly - with young referees, as a mentor.
He says he has achieved more than he ever expected in football. It's great to see he will continue to achieve, by having a hand in the careers of young Kiwis, who one day, like O'Leary, hope to referee at a Fifa World Cup.
