"To be brutally honest I have felt over the two seasons he has been at the club Nani has shown the signs that the Old Trafford stage could be too big for him," Mickey told M.E.N. Sport.
"I know exactly how he felt. I experienced it and it is hard to conquer. Some players are made for United and the spotlight. They revel in it. Some just cannot hack it and never will come to terms with it. Others struggle with it but then learn to cope and grow into it.
"Nani could come into the latter category. There is no doubt the potential is there. He has good technique and can score goals. His performance at Wembley was certainly encouraging. That shows he can do it and you hope it helped him to convince himself he can do it on a regular basis.
"The bottom line is that this is a big season for him. If it is true that he is just one of those players who needed a bit more time to come to terms with life at Old Trafford then this is the season when he has to prove he is over that. You don't tend to get much longer than three years to prove yourself. If it is going to happen then it is going to happen in that time.
"It seems to be all about confidence with him and once he gets over his injury Sunday's effort should give him that."