City's form has been under scrutiny but they remain unbeaten in the competition and are well on course in their title defence.
Mancini said: "I am very satisfied with this performance.
"In the first half we played well created a lot of chances but we were too soft when we had chances to score.
"But we played well and this is the most important thing.
"In the last two games I think we changed something. In our mind we found a good spirit, like last year.
"For us it is very important we start to play well and in the last two games we have scored six goals with our strikers. I think we have been missing their goals."