Despite watching his players cause regular problems for the United defence with their attacking play, Pellegrini admits that it was just as important to prevent their rivals from scoring at Old Trafford.
"For me, it's very important to keep a clean sheet," the Chilean told reporters. "It's important to score goals but today we worked very compactly as a team.
"We didn't give them a metre to make moves in our defence and so we were good in both attack and defence.
"I think we are a very balanced team at the moment."
City are second in the Premier League, three points behind leaders Chelsea with two games in hand.