Your corner is the most dangerous moment of your night

The transition that decides European ties is not the one after a lost tackle, it is the one that follows your own attacking set piece.

Nine players in the box, two outside, and a goalkeeper on the other team who has been waiting for this all evening. He claims it, he rolls it out to a full back who is already running, and eight seconds later your centre back is being asked to defend a two on two in his own half after a sixty metre chase he could not possibly win.

Rest defence at attacking corners is the most under-coached moment in football relative to how expensive it is. Everyone spends the week on the delivery and the blocking runs. Almost nobody spends the week on the arrangement of the two or three players who stay out, and yet that arrangement is the entire difference between a cleared corner and a goal against.

The reason it gets neglected is incentive. Coaches are judged on whether their set pieces score, so the marginal hour goes into the routine, and the counter attack conceded thirty seconds later is filed as a separate event caused by somebody switching off. It was not a separate event. It was the second half of the same possession, and it should be reviewed as one.

Doing it properly costs bodies in the box, which is the honest trade. Keep three out instead of two and your corner is fractionally less threatening. My view is that the trade is almost always worth taking against a team with quick forwards, because the value of a corner is modest and the value of a clean counter attack from a keeper's catch is enormous.

There is a positioning detail I would insist on. The player who stays highest should not be central. He should be on the side the goalkeeper favours throwing to, close enough to force a slower distribution, because delaying the first pass by two seconds is what lets everyone else get back.

The other detail nobody drills is what the two outfield players left back are supposed to do with the ball if they win it. Usually they hoof it, because they are isolated and panicked, and the possession dies. Give them a rehearsed outlet, even a simple one, and a cleared corner becomes a second attack instead of a handover, which over a season is worth more than most set piece routines.

Score from the corner and the tie turns. Concede from it and the tie ends.