The near-post flick-on is not a secret. It's been in football since before most of us were born, every defence in the world knows it exists, and it still produces goals at a rate that ought to be embarrassing for the people defending corners.
The reason is geometric and it's quite elegant once you see it.
What the routine is
An inswinging or flat corner delivered to the near post area, roughly the front third of the six-yard box. A tall attacker attacks it first, ahead of everyone, and rather than trying to head at goal he glances it — changing its direction by maybe thirty degrees so it continues across the face of the goal, behind the defensive line.
Then somebody at the back post finishes it, often from two yards, often into an empty net.
That's it. No trickery, no dummy runs, no clever choreography. And it works, still, at every level of the game.
Why the flick is easier than the header at goal
The first thing to understand is that the flick-on is a much easier technical action than a direct header, and that's the whole basis of the routine.
To head a ball at goal from the near post you have to generate power and change the ball's direction by ninety degrees or more, while jumping, with contact. It's difficult, and the conversion rate is poor.
To flick it on, you barely touch it. The ball is already travelling across goal — you just extend its path and lift it slightly. Minimal contact, minimal power required, and you don't need to win the header cleanly, only to get there first and get something on it.
So the routine converts a hard action into an easy one, and then converts the resulting easy chance into a tap-in for somebody else. It's a chain of downgraded difficulty.
Why it's so hard to defend
Here's the geometry. A defender marking the far post has to watch two things simultaneously — the ball, which is at the near post, and his man, who is next to him. He can't do both, because they're in opposite directions.
If he watches the ball, his man moves. If he watches his man, he doesn't see the flick coming and reacts late. Almost every far-post goal from a flick-on features a defender turning his head at exactly the wrong moment.
The goalkeeper has the same problem, worse. His starting position for a corner is towards the middle or back of his goal, and a flick-on means the ball changes direction after it has passed him. He's committed to a trajectory that no longer exists, and now the ball is behind him, dropping, with an attacker arriving.
There's no good goalkeeping answer to a well-executed flick-on. That's not a criticism of keepers, it's just the physics.
The defensive responses, and why each one fails
Teams have tried a few things.
Put a player on the near post. The classic answer, and it does reduce the flick-on. It also removes a defender from the middle of the box, which is where the ball goes if the delivery is anything other than near-post. So you've solved one problem by creating a different one.
Zonal marking across the six-yard line. Better against flick-ons, because there's a body in the flight path regardless of who's attacking it. Vulnerable to attackers with a running start, since a stationary zonal defender against a runner is a bad matchup in the air.
Man-mark the flick specialist with your best header. Sensible and often effective. But it means your best aerial defender is at the near post rather than in the danger area, and a good attacking side will use a decoy in that role and put the actual threat elsewhere.
Attack the delivery aggressively. Send a defender to meet the ball early and head it clear before the attacker gets there. High risk — if you miss it, you've taken yourself out of the play entirely and the flick-on is now completely unopposed.
The pattern is that every solution creates a different vulnerability, which is why nobody has settled on one.
What makes the good versions good
Having watched a lot of these succeed and fail, the difference usually comes down to two things.
The delivery has to be flat and quick rather than looping. A slow ball into the near post gives defenders time to get there. A driven one arrives before the defensive line has finished shuffling, and the flick specialist only has to be first to a ball that's already past most of them.
And the far-post runner has to start from outside the crowd, not inside it. If he's already in the six-yard box he'll be marked. If he starts from the penalty spot or wider and arrives late, nobody has picked him up, because at the moment the corner was taken he wasn't a threat.
Late arrival is the whole trick with set pieces generally, and it applies here more than anywhere.
A note on why it survives
What I find genuinely interesting about this routine is that it's a solved problem in the sense that everyone knows the answer, and yet the answer doesn't help.
That's rare in football. Most tactics that get widely understood get neutralised. This one persists because defending it requires a defensive team to be perfect in a situation where the attacking team only needs one player to get a touch, and those odds don't change no matter how much video analysis you do.
Simple, old, entirely predictable, and still worth several goals a season. There's a lesson in there somewhere about complexity being overrated.