United briefly extended their lead at the top of the table to 18 points with a 1-0 win at Sunderland, the seventh on the trot, although reigning champions Manchester City reduced the deficit once again a few hours later with their victory over Newcastle.
The pair meet at Old Trafford next weekend and Ferguson told Sky Sports: "We have got to win four games, I think to get there, but the important thing is to focus on the next match, and that's Manchester City at home."
He added: "I think the players have galvanised themselves, their team spirit, their concentration, their focus in every game - and it's 25 wins in 30 league games, which I think is a record, and that's all down to the efforts of the players."
The victory at the Stadium of Light extended United's run to 18 league games without defeat and means they have collected 50 of the last 54 points they have contested.
United have an FA Cup quarter-final replay trip to Chelsea to come first, and midfielder Michael Carrick said: "It's obviously getting closer because it's one game less and we have won again. But that's all it is. We have still got to go again.
"We have got another game on Monday and then obviously City next week, so we will keep going."
The win was secured by Titus Bramble's 27th-minute own goal, and although Sunderland, who have now not won in eight games, rallied after a lacklustre first-half display, they rarely looked like snatching a point.
Bramble can count himself unfortunate - Robin van Persie's shot clipped full-back Phil Bardsley and looked to be flying wide until it hit his knee and nestled inside the far post.
Asked if it was his goal, Van Persie, who had not scored for his club since February 10, said: "Of course, there's no question about that. It's been a while, so it's always good to score again. It was a really important goal. Today, it was all about the three points, so we got them."
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