Arsenal are two goals ahead after the first leg in London but head to the cauldron of the San Paolo Stadium knowing that the Italians are more than capable of staging a comeback.
Xhaka said: "They have to come (at us). We had a good result at home, we have to stay compact in defence, good balance and if we score one away goal I think the game is finished but they are strong enough to beat us if we are not ready.
"It will not be easy in Napoli as you have seen with Liverpool there or Paris [Saint-Germain]. Napoli have a good team, especially with their fans, but 2-0 is a good result and I hope we can go to the semi-final."