The forward's two goals took his tally to a club record-breaking 10 against Manchester City, and he also became the youngest to the 150 goal mark in Premier league history.
Rooney's double helped him crack the 150-goal barrier, taking the 27-year-old forward to 151 Premier League goals all-time and becoming the youngest member of the exclusive company. A record-breaking 10 of those have come in Manchester derbies, with Rooney snapping the mark of nine previously held by Sir Bobby Charlton.
"Of course, it's great to score here, but it doesn't matter whether it's against City or not," Rooney told Sky Sports. "I'm scoring for Manchester United and enjoying it. Obviously it's a great day for us to win here. They've had a great home record and to spoil that is a great feeling.
Having lost at home and away in the league to their rivals last season, the England man's two goals put the Red Devils in front before Robin van Persie put down a City comeback with his stoppage-time free kick.
"It's fantastic. It's great for us to go six points clear against our closest rivals, especially after what happened last year. We've waited a long time for this to happen," Rooney said. "[The game was] crazy," Rooney added. "It's been like that all season for us.
"To lose a two-goal lead ... to be fair, we were hanging on a bit at the end. They had a couple of chances and a bit of magic got us the three points."
Van Persie's late strike capped a fine performance in his first Manchester derby but the Dutchman remarked of his goal, "Anything will do – just to win. We had a good start because of Wayne, two really good, clinical finishes, good attacks and then we went into control, which was good.
"City always come back and we knew that so it's a really special way to end this game, to get the three points in a dramatic way.
"Wazza asked me [before the free kick], he said, 'What are you gonna do? Are you gonna shoot or are you gonna cross it?' I said, 'I think I'll have a shot.'"