Nani was the latest of three players to have missed from the spot so far this term when his kick was saved by Galatasaray goalkeeper Fernando Muslera.
Robin van Persie and Javier Hernandez had already missed from the spot before last night's latest failure, the problem is that after Wayne Rooney there is no spot kick specialist and he is out injured.
Ferguson put Nani's miss down to nerves, but also admitted that van Persie maybe should have been the man to take the kick.
Asked why Nani took the spot kick, he told the Manchester Evening News: “To be honest with you I had no idea. I think Nani just ran and grabbed the ball.
“I thought Robin should have taken it, to be honest with you. I think we will have to decide before the game, that was my fault, I should have done that.”