Robin van Persie hailed his late winner as a special way to win the Manchester derby.
The Dutchman's deflected injury-time free-kick earned United a 3-2 win at the Etihad Stadium after City had come back from 2-0 down.
"We had a really good start, because of Wayne two really good, clinical finishes," Van Persie said on Sky Sports 1.
"We were in control, but City always come back.
"It's a really special way to end this game, with the three points in a really dramatic way."
Rooney praised his team-mate, saying: "We work on that on the training ground and I had no doubt he could score from there."
The win moved United six points clear of City at the top of the table and ended the hosts' long unbeaten home record.
"To go six points clear, to beat our closest rivals, we're delighted. We're going to celebrate."