Ferguson signed De Gea in a £18million deal from Atletico Madrid earlier this summer as a replacement for Edwin van der Sar, who retired at the end of last season.
De Gea failed to impress in last weekend’s Community Shield clash with rivals Manchester City.
“When free-kicks come in and defenders are converging, the goalkeeper has no chance,” said Ferguson.
“The delivery was so good.
“It was interesting there was no criticism of Joe Hart for our first goal, yet it was exactly the same type of goal.
“All it needs is a fraction of a touch and the goalkeeper is dead. If he comes for it, he ends up looking silly.
“De Gea will be fine. He will play on Sunday. That is the reason we spent £18million on him.”
