Pep's never done defence just throws money at it. Because they've been so much better than the rest they've never had to rely on it and have never been exposed domestically until recently.
In Europe it's a different story, since leaving Barca he couldn't match his immediate predecessors European achievements at Bayern, not even getting near, and has yet to even match Pelligrini's semi final achievement with City, a real failure for him.
Domestically the same weaknesses are finding him out and any fear factor long gone.