Shinji Kagawa's hat-trick and a late strike from Rooney secured a victory which moves the Old Trafford side 15 points clear at the top of the Premier League table ahead of Manchester City's trip to Aston Villa on Monday night.
And despite Tuesday night's last 16 tie against Jose Mourinho's side, Sir Alex Ferguson opted to pick a near-full-strength team, with the likes of Robin van Persie and Nemanja Vidic included in the starting XI.
"I'm sure you can see by the team the manager picked, he put a lot of experienced players out and made us aware that the Norwich match was more important than the game on Tuesday," Rooney told MUTV.
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Kagawa staked his claim for a place in the team against Real Madrid with three goals and Rooney had only positive things to say about the summer signing from Borussia Dortmund.
"He [Kagawa] was fantastic, he keeps putting himself in positions where he can maybe get a shot at goal or play someone in," the 27-year-old enthused.
"If you can see him and pick him out, he's cool with his finishes as well. He works hard and he’s a good team player, and we're all delighted that he got the three goals."
The win saw Sir Alex Ferguson's men keep another clean sheet - their fourth in a row - and Rooney believes that run of form at the back will stand the team in good stead ahead of their meeting with the Spanish champions.
"Early on in the season we were conceding too many goals," Rooney added. "We seemed to have coped with that, we're not conceding and we're scoring goals so we're in a great position at the minute.
"So, hopefully we can continue for Tuesday. Obviously it is two of the biggest clubs in the world, so it will be an exciting night, we're all looking forward to it.
"Three points against Norwich were vital to put us in good spirits for the game on Tuesday."