In front of Tom Cruise, Wayne Rooney had become United's Manchester derby Top Gun with his first-half brace.
It made him the Red Devils' most prolific scorer in clashes against City, in addition to confirming him as only the sixth - and youngest - player to reach 150 Premier League goals.
But when Yaya Toure and Pablo Zabaleta turned the contest on its head, Ferguson admitted he would have been delighted with a point.
"You have to give credit to City," said the United boss.
"They kept fighting and battling.
"They have this great record of scoring goals and when they got the second I thought, `I will take the draw'."
Van Persie had other ideas, adding to his already impressive reputation by scoring his 14th goal of the season to ease United six points clear.
"It got a little deflection but it was a terrific hit," said Ferguson. "His whole game was fantastic. He has kept them on the back foot."