Wayne Rooney scored another late winner to put the Premier League leaders 10 points clear for 24 hours at least and Ferguson paid tribute to the defence, who have conceded just 16 goals in 12 away games this season.
"We had so many chances. It was a terrific football match and it was an excellent result, and I'm very pleased for us," said the Scot.
"They had some great chances. Our keeper (David De Gea), Jonny (Evans), Rio (Ferdinand) were terrific and we had a few chances ourselves, the second half in particular.
"In the first half we hit the woodwork three times but we deserved to win. They have had a great home record over the years and it is a very important result for us.
"It's a good position (we are in) we are pleased. Tonight you can look at the performance of the players. They put their bodies on the line, blocking shots, great headers out of defence, really determined effort by the players.
"It was similar to when we played here a few years ago when Cristiano scored near the end and we went on to have an undefeated run after that. It was around the same time too.
"It was a well-taken goal and Rooney was unlucky before that, hitting the post and having a couple of shots saved by the goalkeeper."
De Gea has come under fire after some uncertain performances this season, but Ferguson was quick to single him out for praise.
"It's not fazed him, for sure," Ferguson said of the recent criticism. "He enjoyed this game. It's a challenge and it's not easy for a young goalkeeper, but he's enjoyed tonight."