The 22-year-old has had to deal with a large amount of criticism ever since he joined United from Atletico Madrid in the summer of 2011.
However, despite admitting that the Spaniard has wobbled, Ferguson has insisted that he is now performing to a high standard.
"He's like a young kid," he told reporters. "He wobbles, he gets up. He wobbles, he gets up. Eventually he walks. The boy is walking now."
De Gea has made 25 appearances in all competitions this season.