If you start to look at all his individual actions (such as going for headers v Benteke with no hope of connecting) you start to spot more stuff & it makes no sense that we haven't let goals in.
But then on the other hand he & City, did some good stuff v Shakhtar, when they did get in behind us, preventing crosses getting through etc, so perhaps it's best to do what some on here do, & just not notice all the potentially disasterous mistakes, unless they actually cause disasters.
Utd are doing it with Phil Jones every week. They seem to feel confident enough, & are content ignoring it.