Our two defenders split and nobody protects the middle

The first thing I’d fix is the distance between the two defenders when the ball starts moving. Getting wide in possession is useful, but they need to recognise that the picture changes the moment the pass is played or possession becomes uncertain. I’d give them a simple reference: “When one goes wide, can the other still protect the middle?” Then use a small game starting from the goalkeeper. If the attacking team loses it, the opposition can score quickly through a central gate. That makes the danger obvious without stopping the game every time. At U10 I don’t want the defenders thinking in terms of a fixed back line. I want them learning that one can stretch to receive while the other stays connected enough to deal with what happens next.