Mancini said: "I don't know how many times we crossed and didn't have any players in the box. This cannot happen.
"We have four good strikers, but I want them to work harder and to score when they have a chance - they are strikers and this is what they are there for.
"They have to defend as well, of course, but they need to put chances away. I am happy with the performance, but not with what happened near their box. We are in second position and we don't like that."