Fabio produced arguably his best performance in a United shirt for the 1-0 win and Ferguson told MUTV: "He was absolutely outstanding.
"The boy is a magnificent player at only 18 years of age. Absolutely first class."
United defender Rio Ferdinand added: "Fabio is a mirror image of Rafael in the way that he plays. He's a fantastic player and the lads really enjoy having him in the team. He's enthusiastic, he's willing to learn and wanting to try new things. He's a breath of fresh air."