“It’s a difficult place to come to, Real’s home record is outstanding,” Ferguson told a news conference.
“I was a bit disappointed with how deep we defended which gave Real a lot of opportunities for crosses and shots.
“Luckily David De Gea was excellent. He made three or four really top saves in the game.”
De Gea has come in for criticism, since moving to Old Trafford from Atletico Madrid for around 20 million euros in 2011, with his slight build cited as a weakness in the hurly-burly of the Premier League.
Ferguson has stood by him, however, and he made superb blocks from Fabio Coentrao twice, the second with an outstretched boot, and another from Mesut Ozil in a one-on-one.