He needs to replace Naby
He needs to add that rough dimension to the team or he will have similar (but less pronounced) problems to Wenger.
Teams are not always going to play ball. Real came to frustrate. Like SAF used to do to Arsenal or Jose's chelsea used to do to everyone (except Rafa).
Klopp didn't know what to do.
Like SAF didn't know what to do in the 2009 and esp. 2011 finals.
Look at how Newcastle physically dominated Arsenal the other day. It is that roughhouse element that is missing from your (and Citeh's btw) squads.
Naby ain't gonna make it and I bet Klopp starts to make hard decisions to shake up the squad and better prepare them for the future.
Henderson and Thiago are not the future and Fabinho just came back from injury. The fact that even under those circumstances Naby could not be trusted to start this game tells you all you need to know about whether Klopp thinks that he is of the required standard.