Looked at in isolation, yesterday was arguably worrying- they had five touches in the entire 90 minutes in our box and still scored twice. Also, there is something - again, looked at in isolation - worrying that both Stokes goals came from attacks down our left, and our first choice left back is out til April.
That said, the defence has been excellent all season. Delph was in particular outstanding against Chelsea, and very competent against Shaktar. I worry about what happens if he picks up an injury, as he very well might, but for the time being he looks like he can do a job there. More importantly, he fits within pep's style of playing - our second goal yesterday came from the back five working the ball forward through Stoke's high press. There were 13 passes between Otamendi's back heel and Sterling's finish, and a good half of those were between the back five. I think Pep would sooner have a back five that can do this, even if the fullback gets skinned once every two or three games, rather than a back five who are good at winning tackles and headers but not much else.
And of course this has to be seen in the context how just how fucking good we are. In one way, it doesn't matter how bad your defence is if the other side can't get the ball off you.