I was just about to post exactly this. If Chelsea go toe to toe with us, we can and probably would win imho.
But if they sit back, they are extremely well organised and good at defending and we will struggle to break them down. Inevitably we would end up being caught on the break and looking at our defensive frailties, I think it's unlikely we'd keep a clean sheet if it goes that way.
Bizarrely; our best tactic might be to sit back, let them have the ball, and then him *them* on the break. In a way, a bit like how the Barca game played out
Our defending has looked shaky at times because often we are over extended high up the pitch. When we stay compact and organised we actually do defend pretty well and we have the quality to hurt them if we nick the ball back off them when they are building an attack of their own. Fernandino will be our most important player imho.