"One of the encouraging things is the goal difference is helping us," he said. "That's deserved because we've attacked all season and have put an attacking emphasis on our game.
United put one hand on the title with Sunday's 2-1 victory over Arsenal and Ferguson admitted the competition has been ferocious this season.
"It's been a really competitive league," he said.
"It's very easy to dismiss them now but when we beat Arsenal we knew we were right back in the ball park of going for it.
"Last night's result was a bonus for us. Our hardest game was at Middlesbrough earlier this month - we dropped two points there.
"It was a massive result for us against Arsenal. It could still go to the wire and we can't take it for granted.
"We could lose to Chelsea and we could lose all our remaining games. It's a very difficult league these days."