The space behind the wing-back 🎯

In Napoli's 3-4-2-1 against Milan, watch Spinazzola on the left. When he pushes high, the space behind him is not the problem. The problem is who fills the channel between Olivera and Juan Jesus.

Milan set up in a 3-5-2 with Bartesaghi and Saelemaekers as the wide runners. If Napoli's midfield four cannot slide across in time, that channel opens for a simple pass into the gap.

Conte's shape relies on Lobotka screening the middle. When he steps out, the passing lane to the edge of the box disappears. That is the trigger to watch.

Look at the space behind the wing-back, not the ball.

Question: When a wing-back pushes high, who should be responsible for covering that channel, the wide centre-back or the holding midfielder?