"For Manchester United, over 20 hours without conceding a goal is extraordinary because normally we get scorelines like 4-3," said Ferguson.
"It is great credit to the players. I am very proud of them."
Although he suggested on Friday an element of caution had crept into his side the longer their defensive record has remained intact, Ferguson will not be too concerned as long as United remain top of the Barclays Premier League.
Edwin van der Sar has now claimed a British record for the longest amount of time without conceding a league goal, with the veteran Dutchman sure to keep the Red Devils defence on their toes when Fulham head to Old Trafford on Feb 18.
"The record is a great motivation for the players, particularly Edwin," said Ferguson.
"He has everyone jumping out of their skin at the moment."
The result keeps United two points ahead of their only realistic challengers Liverpool, with a game in hand, and it would be a surprise if they did not end the season level with their long-time north-west rivals on 18 championships.
Yet Ferguson is refusing to get carried away. Aston Villa may be five points adrift, with Chelsea and Arsenal even further behind. But the United manager is taking nothing for granted.
"Mistakes can be made," said the United boss.
"We had an 11-point lead over Arsenal in 1998 and lost the league, so we are not counting our chickens.
"We shouldn't either because this game can come and bite you. This is a fantastic result and performance. It is time to kick on."