The Red Devils currently sit top of the Premier League table, having scored 24 goals in their opening seven matches.
Although their net has been breached on just five occasions, United have conceded more goalscoring chances to their opposition than any of their title rivals and Ferguson is seeking an improvement.
"Let me tell you, I'd be quite happy winning every game 1-0," said Sir Alex, according to The Sunday Express.
"We're playing a wee bit open, that's for sure, both in the league and in European games. We are very attack-minded at the moment, but we have to be tight at the back.
"The defenders we have been using this season are young, remember, so they are going to get better as the campaign goes on."
United's next match is a trip to Liverpool next Saturday.