City were fortunate to win after a controversial red card to Laurent Koscielny early on at the Emirates Stadium which effectively killed the match.
“It was an important victory because it’s difficult to play and win here,” said Mancini. “United are a really strong team. In this moment they play very well.
“But the season is long. It’s important for us to be there, close with them, and we will arrive the moment they lose points. We’re under pressure maybe but everything can change.”