Ferguson's side hold the advantage going into second leg at Old Trafford, as Carlo Ancelotti's men see their stoppage time penalty shouts fall on deaf ears at Stamford Bridge
Rooney has once again been the centre of attention for the back pages since his foul-mouthed rant after netting his hat-trick against West Ham at the weekend, and the glare of the media's eye was trained firmly on the striker again.
So much so that the milestone reached by Frank Lampard in this game - 500 appearances for the club - were barely mentioned in the build up.
Lampard was keen to force his way centre stage and on 18 minutes he almost did in the best possible fashion, when a slick and incisive passage of play involving Lampard and Ramires resulted in Didier Drogba smashing at shot high at Edwin van der Sar, with the Dutchman proving equal to the effort.
In the corresponding league fixture in March, it was Rooney who broke the deadlock and once again that pattern emerged.
A fantastically long cross-field pass initiated by Michael Carrick was deftly controlled by Ryan Giggs, who sniffed an opening and headed for the byline. The Welshman spotted Rooney, and fed the ball into his path for the striker to beat Petr Cech low to his left with the lightest of touches, which found the net off the foot of post.
This time Rooney maintained enough self-control to celebrate the goal in a manner more palatable for the TV audience. No contorted face, no turning the air blue, only sheer elation and joy as he gave his side a valuable away goal.
With this, United were in a desirable position, and they calmly went to seeing out the half with minimum fuss, this was tested to the maximum when just before the half, a cross from Drogba was lightly back-heeled by Fernando Torres only to come back off the post. Lampard’s tap on the rebound looked a sure goal but an excellent display of defensive awareness from Patrice Evra kept Chelsea at bay.
The second half didn’t start well for the visitors as Rafael felt the full force of Drogba who clattered into the fullback. He was taken off the field for treatment and his return to the action was short lived. Only moments later he dropped to the ground in pain before leaving the field on a stretcher. Ferguson was forced into moving his pieces around, Valencia dropped in the right back slot and Nani entered the fray onto the right wing.
All smiles now | Chelsea the ones left cursing as Rooney scores vital away goal
As the game continued Chelsea clearly became frustrated. Chances were not falling for the Blues and this was due in no small part to the rigidity of the United back four. With Rio Ferdinand making his first appearance since February, he resumed his partnership with Nemanja Vidic and the pair showed the steal which so much of United's success has stemmed from in recent years.
And Ancelotti was forced to make changes in search of a way back. Yuri Zhirkov and Drogba were replaced by Flourent Malouda and Nicolas Anelka. But still United held back the tide. Chelsea began to throw men forward and this tactic almost paid off, when Ramires' run in to the box was halted by Evra who was fortunate not to concede a late penalty, as the French full-backs' legs wrapped round the Brazilian before hauling the former Benfica man to the ground.
That wasn't the last of the penalty box action, as this time the referee blew his whistle, only to caution Torres for diving following the close attentions from Valencia.