The corner that undid Milan's shape

Sassuolo 1-1 Milan on Sunday. Milan scored on 63 minutes through Rabiot, a clever run behind the line from a Modric pass-8. Five minutes later, Sassuolo equalised from a corner-1.

Watch the corner again. Milan's box was packed, but the marking was loose. Cas Odenthal fired through the crowd from close range-3. When a team scores and then concedes from a set piece almost immediately, the issue is not the formation. It is the organisation inside the box.

The four-back shape had given Milan better control in the first half-11. But controlling open play and controlling a corner are different jobs. One demands structure between the lines. The other demands discipline inside the six-yard area.

Check who picks up the second ball before blaming the system.

Question: When a team concedes right after scoring, do you look at the shape or the marking first?