The Premiership giants require a win against Benfica in Lisbon in their final group game, or a draw should Villarreal manage to beat Lille.
"I think our form is pretty good now and I think the confidence is there," said Ferguson.
"We have a big job to do but it is not unusual for us to be in this situation and I am still optimistic.
"Our form is getting better and it must help us that Benfica have to win too.
"It will be a great atmosphere, in a great stadium and while pressure comes in all forms, I am expecting a great game.
"We can't go into the game thinking about anything other than winning it. You could say the same thing about everyone else, so in that sense it is a very open situation. We know every team will be trying that's for sure."