I have to say that Sarri made a big mistake leaving Napoli for Chelsea.
At Napoli he had a group of players who played football how he wanted them to play it, a group of players who respected his authority as a coach. Napoli played beautiful football under him and he wasn't under pressure to win trophies. The ideal marriage.
Now he's at Chelsea. A group of players who don't know how to play possession football, don't respect him as a manager, and he's under pressure to win trophies. A nightmare scenario.