On February 12, 2011, Rooney scored a stunning bicycle kick against City that has gone down in the history of Manchester Derby. Man Utd beat Man City 2-1 at Old Trafford.
Talking about this overhead kick, Rooney described it as his most important goal for Manchester United.
"The deflection [from Nani's cross] actually helped me, because it slowed the ball down and gave me time to adjust myself, turn my body.
"To be honest, I just thought I'll go for it. I wasn't having the best game, and thankfully it's gone into the top corner."
Asked if it was his most important goal, Rooney said: "I think so. We went on to win the league that year and it was a big game for us."
Rooney also revealed that City goalkeeper Joe Hart still believes the effort came off his shin, but the United man insists that's an even harder skill.