With QPR and Wigan to come over the Easter period, Manchester United look well placed to take maximum advantage of Manchester City's recent dip in form.
But Ferguson said: "We know how quickly football can turn on you and bite you. You can look at all the fixtures and say all those teams are fighting for their lives. And they are the kind of games you know will be tight."
Ewood Park has never been an easy place for United.
Ferguson's team have emerged victorious on just two of their last 11 visits, a record that is worse than against any other north-west rival, including Liverpool and Manchester City.
Two seasons ago, United were held to a goalless draw that ultimately cost them any hope of retaining their title.
And even last year, when they only needed a point to get it back, the Red Devils required a late Wayne Rooney penalty to start the celebrations.
"The game at Blackburn has always been a difficult match," said Ferguson. "It is a local derby and tends to be a bit feisty.
"Last season we were lucky enough to come back from a goal down to win the league.
"But it will be a very difficult game. That is the way it is going to be from now until the end of the season."