And as United pursue their 20th title, Ferguson was pleased to overcome Liverpool, whose total of 18 was the previous record.
He said: "It doesn't matter what position we are in the league, Manchester United-Liverpool games are a fantastic challenge between two of the most successful teams in the country and those three points are hopefully very important."
Ferguson enjoyed Van Persie's 21st goal of the season and felt United, who were dominant before the break, could have had victory sealed by half time.
"It was a great build-up, terrific football and a great finish. We should have been maybe three or four up," he said. "Until the second goal, we were magnificent. It was as good as a performance we've had for a long time."
But the United manager acknowledged he had some nervy moments after substitute Daniel Sturridge brought Liverpool back to 2-1 by scoring on his league debut following his £12 million (Dh71m) move from Chelsea.
He said: "When they got the goal they were inspired – their supporters got going and it was hard work after that and I'm just glad we won the match."
Brendan Rodgers, the Liverpool manager, refused to complain about the award of United's winner, even though Vidic was proved to be fractionally offside.
"I am more disappointed with how we defended it," he said, after both Vidic and Patrice Evra were left unmarked. "We have got to do better at the back post."
Rodgers said Sturridge was not fit enough to start but was delighted with the impact he made in the second half.
"This is a boy who can be a real top striker and he is going to score many goals for Liverpool. He is a goalscorer. He is going to be a terrific signing."
Defeat leaves Liverpool 24 points adrift of the league leaders but Rodgers said that is due to Liverpool's lack of strength in depth, rather than problems in his starting XI.
"We are not 24 points behind in quality," he said. "The points difference is due to the squad. Once we close the gaps in the squad in the transfer windows, I have great faith we will be able to challenge."
United were without Jonny Evans, who hurt a hamstring, and suffered another injury worry when Ashley Young left Old Trafford on crutches.