IT is one of the great certainties of sport that someone is going to make a mistake that makes the difference between winning and losing.

A missed penalty, a dropped catch, an untimely stumble. It goes with the territory. Usually team mates and coaches rally round with support knowing that either it has happened to them in the past or that it could be them next week.

But Harlequins’ Ben Botica made a blunder on Saturday which even their usually bubbly director of rugby Conor O’Shea was unable to put a positive spin on.

The ball was in Botica’s hands behind his own try line and to all intents and purposes the game was won. All he had to do was touch it on the ground and Quins would have beaten Northampton.

Instead the replacement fly-half elected to kick the ball, an act which of course you regularly see at the end of rugby matches and, if it ends up somewhere near Row Z, would have had exactly the same effect of ending the game.

But whether it was a lack of concentration or just a miskick, the ball never reached touch and Ben Foden caught the ball. From that stage on the defeat was inevitable. Saints attacked a Quins line who mentally probably thought the game was already over and it was Foden himself who ran in a try which gave Saints victory and could have hugely damaging repercussions if Quins fail to clinch a top-four finish.

O’Shea wasn’t mincing his words afterwards, mentioning it was probably just as well he hasn’t had chance to discuss the faux pas with Botica.

“That was nothing short of unbelievable and unforgivable,” he said.

lamenting the fact that a fine team performance had been ruined by one dreadful piece of decision-making.

You can only imagine the New Zealander wasn’t looking forward to training this week, but it’s only a month since he played a major role in Saracens’ first defeat of the season.

And that’s always the fine line in sport – the hero one week can be the villain the next. All the best-laid plans can turn to rust on one misjudgement.

Some mistakes feel crueller than others and Botica’s was one you wouldn’t wish on anyone.