United have not conceded since the 6-1 drubbing.
Vidic said: "After the City game we realised we had to play as a team, we had to defend better. And I think we have done that in the last four games.
"We take a lot of satisfaction from the fact we have won all four games but if you look at the performances we can definitely do better.
"The goals will come again if we keep winning games because the confidence will come back. It is important to show solidity, to work hard as a team, and to keep clean sheets.
"That is the way you win league titles and go a long way in the Champions League.
"You can't play great football, nice football, going forward all the time because that allows teams to create chances. You have to find a balance.
"Obviously we can play better in terms of passing, creating chances and scoring goals but we've got to find the right balance. And while we're trying to find that balance the most important thing is to keep winning games."