By Phil McNulty
Chief football writer at Old Trafford
Wayne Rooney's dramatic stoppage-time header sent Manchester United into the Carling Cup final and wrecked Manchester City's hopes of reaching a first major Wembley showpiece in 29 years.
Carlos Tevez looked to have sent the semi-final into extra-time when his sensational backheel flick after 76 minutes answered second-half goals for United from Paul Scholes and Michael Carrick.
But Rooney, United's man of the moment, demonstrated once more that he is in the form of his life by heading Ryan Giggs's cross past City keeper Shay Given to send Old Trafford wild and set up a final meeting with Aston Villa on 28 February.
For City, it was a grim and heartbreaking echo of their Premier League defeat at Old Trafford earlier this season when Michael Owen's last-gasp goal gave United a 4-3 win.
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Roberto Mancini's side showed admirable composure in the cauldron as the battle unfolded, and Tevez and Micah Richards brought fine saves from Edwin van der Sar as they went in search of the goal that would have put them at the gates of Wembley.
But Scholes struck from 18 yards early in the second half, and when Carrick put United ahead on aggregate 19 minutes from time, City's bold bid to show they are now serious rivals to the Old Trafford empire looked in tatters.
Tevez, still very much the villain in the eyes of United's fans after his summer move to Eastlands, threatened to deliver a dream script with an imaginative finish, but Rooney is penning his own big stories these days and it was almost inevitable that he would write the final chapter in this domestic squabble.
Security was heightened after trouble at the first leg, and United's win was marred by a second-half incident when Craig Bellamy was felled after he appeared to be struck on the head by a coin, with a bottle also thrown.
It did little to sour the Old Trafford elation at the final whistle, and how they enjoyed putting City in their place once more.
The anticipation outside Old Trafford was matched by the crackling atmosphere inside - stoked by the words exchanged between the two clubs since the contentious first leg.
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United set the tempo early on, but once City gained a measure of composure they created the better opportunities in a tightly contested first half.
Tevez, inevitably, was a central figure and Rio Ferdinand was fortunate to escape punishment from referee Howard Webb when he caught the Argentine in the face with a swinging arm as they tussled for possession.
Bellamy tested Van der Sar with a header from Shaun Wright-Phillips's cross, and then set up an even better opportunity which was wastefully squandered by Tevez after 28 minutes.
The former Manchester United striker arrived on the end of Bellamy's perfect cross, but made life too easy for Van der Sar with his headed finish.
United's response was a low shot from Giggs on the edge of the area, but Given was perfectly positioned on the edge of the area to make a routine save.
Tevez pulled City back into the tie with a classy flick
The pressure was on United to make the running at the start of the second half, but it was City who almost snatched the lead when Richards brought an athletic save from Van der Sar with a rising drive.
Bellamy was then the victim of a shameful incident as he went to take a corner, going to ground after appearing to be struck by a coin, with a plastic bottle also landing in the striker's vicinity.
United made the breakthrough they craved after 52 minutes, and it came from Scholes, who had been at his most influential amid the midfield mayhem.
He was lurking in familiar territory on the edge of the area, and when a loose ball arrived at his feet he drilled it unerringly beyond Given.
The tie had swung towards United, and the balance shifted even further when Carrick added a second with 19 minutes left, just as City boss Mancini prepared to introduce Emmanuel Adebayor in an attempt to wrest back some control.
City failed to clear in the area, and when Fletcher laid the ball back to Carrick, he steered a composed finish across Given into the bottom corner.
Rooney, so deadly in front of goal in recent times, then wasted a glorious opportunity to set the seal on United's night when he somehow turned his shot wide of a gaping goal from eight yards after being played in by Nani.
And how Tevez made him pay just minutes later when he brought the tie level with a stunning piece of invention.
Ferdinand stooped to head Bellamy's cross away, only to find it removed from his forehead by an acrobatic backheel from Tevez that flew low out of the reach of Van der Sar.
Just as Old Trafford was bracing itself for the tension of an extra 30 minutes, United mounted a typical late surge that brought the stoppage-time winner that booked their Wembley ticket.
Given saved superbly from Fletcher, but when City failed to concentrate at the resulting corner, Giggs delivered for Rooney to head past the powerless the Republic of Ireland goalkeeper.
Ferguson danced with delight in the dug-out as City were forced to put their plans to topple their illustrious neighbours on hold.
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