The Red Devils were beaten 2-1 by neighbours Manchester City to see their lead reduced to 12 points with seven matches remaining and Ferguson admitted he had not yet pencilled in the title after seeing his side go down to the reigning champions.
"If you look at the history of our club, we always make it difficult for ourselves," Ferguson told Sky Sports 1.
"We have our supporters hanging on the edge of their seats every year.
"We have a 12-point lead but we won't be taking anything for granted.
"The plus point from today is that we only have seven games left now. As each game goes along you whittle them down.
"We have Stoke on Sunday. The support will be great and we will have a go. We have to kick on now."