Striker Danny Welbeck has been singled out for a lack of goals, while keeper David de Gea's performances have also come under close scrutiny.
But Fergie insists they have simply needed time to establish themselves in the United set-up.
He said: “Danny’s goal against Madrid won’t do him any harm.
“He is not a boy who lacks confidence and wasn’t fazed by the occasion.
"Danny has been with us since the age of nine, so it’s a great testimony to the development we do with young players.
“Nick Powell and Adnan Januzaj were in the reserves on Monday and you say to yourself, ’These are definite Manchester United first-team players’.
“They have outstanding qualities. We can see that. They can see that in trusting us to map out their careers, they can get to Danny’s level."