United won 1-0 thanks to a Nani's first-half goal to stay alive after leaders Chelsea had beaten Liverpool 2-0 at Anfield earlier in the day.
Ferguson's side will host Stoke next weekend trailing the Blues by a point and needing them to drop points at home to Wigan.
And while their fate is not in their own hands, Ferguson has not given up.
"All we can do is win our game next week," he told Sky Sports 1.
"Obviously I wouldn't say its a sealed result against Wigan by any shadow of a doubt.
"They're a good team, they'll have a go and you just never know. It's a crazy game.
"Maybe we are clutching at straws a little bit. It is important for us to win in front of our home fans and play the right way.
"It would be a incredible achievement for us. At the least we have stretched it (the title race) and kept the nerves going."
Ferguson was slightly disappointed with his side's display today as United missed a number of chances, most notably Dimitar Berbatov, to win by a more convincing margin.
"One-nil is not a healthy score away from home," the Scot added.
"It was perhaps due to careless finishing. It looked that way. There were a lot of great chances. But we got there, that is important."