A low block fails in the six seconds after the tackle

Teams drill the shape endlessly and then lose the ball again immediately, because nobody rehearsed the exit.

Watch the tackle, then keep watching. That is where the argument is. A side defending deep will spend most of the week rehearsing the shape: distances between the lines, who steps to the ball, who tucks in behind. Fine. All of it fine. Then the ball is won on the edge of the box and the nearest teammate is thirty five yards away with his back to the play, and eleven seconds later the same attack is coming again down the same side.

Containment is not the hard part. Any competent professional group can sit in two banks and make a pitch feel small for twenty minutes. The hard part is that sitting deep pushes every one of your passing options into the opponent's half, so the moment you win the ball you own a problem you created yourself.

I think most low blocks are built backwards. Coaches start from the defensive shape and treat the exit as an afterthought, a clearance and a footrace. But the exit determines whether the block gets a rest. If your first pass goes forty yards to a lone striker with two centre backs on him, you are not clearing the ball, you are lending it. Three minutes of that and the block is not compact, it is drifting and blown.

The teams that actually survive a siege do one specific thing. They keep a genuine outlet on the far side, usually a wide player who defends much narrower than he looks and who is told, explicitly, not to track the full back beyond a certain line. That looks like laziness. Pundits call it laziness. It is the only thing between the block and a slow death by repetition.

The other half is the goalkeeper, and here I would be blunter than most. A keeper who cannot hit a forty yard pass into a channel is a liability in a deep block regardless of how many saves he makes, because every recovered ball comes back to him and he is the one man on the pitch with time.

There is a number I would like to see and never do. Not clearances. Not duels won. The share of turnovers where the defending side still has the ball ten seconds later. That single figure separates a block that is working from one that is merely holding on, and the two look identical on television until the eightieth minute, when only one of them is still standing up.