To be fair, it was the Arsenal defence, not just Cech.
But it highlights the posture taken by the team. Don’t score, then hope not to concede. Aim not to concede, then try to score.
Get defensive cover. Forget Aubameyang, who will only become another Sanchez. Plug the hole where it matters.
Maybe a change in thinking is required, which is where a new head may be better.