Second-half goals from Anderson and Danny Welbeck allowed United to set a new record of 19 successive home wins in the Premier League. They also stayed top of the table, by a single goal from Manchester City.
Ferguson said: "Our home record has been fantastic for two seasons now. This was not a good performance but we were gritty and we never gave in. That is a fantastic quality to have."
Ferguson admitted United could have fallen behind just before Anderson's opener, when Anthony Pilkington nipped in to rob Antonio Valencia just outside the home box. But after Pilkington had rolled his shot narrowly wide, United seized the initiative.
The Reds boss said: "I don't expect Anderson to score with a header. I felt we needed someone to get hold of the ball up front. Danny Welbeck did that - and he also got another goal."
Ferguson also explained his decision to select Anders Lindegaard for his Premier League debut in preference to normal goalkeeper David De Gea.
He said: "It was an opportunity to play Anders. He is going away with Denmark this week but probably won't play, whereas David is likely to play twice for Spain's Under-21 team."
Asked if he felt his Norwich side deserved more from their trip to the north-west, Canaries boss Paul Lambert said: "Yes, but that is the game. If you do not take your chances, they can come back to haunt you.
Manchester United are one of the best sides in Europe. They scored eight against Arsenal not so long ago.
"If you switch off for a millisecond they will punish you."