Federico Macheda scored a stunning late winner as Manchester United regained top spot in the Premier League.
The 17-year-old substitute turned in the box and curled in a superb strike to make his debut the stuff of dreams.
Cristiano Ronaldo had opened the scoring from an indirect free-kick after a James Milner backpass, before John Carew's header restored parity.
Gabriel Agbonlahor headed Villa in front only for Ronaldo to level with a low shot and Macheda to snatch victory.
It was an incredible finish to a match that twisted and turned - and had looked to be going the way of Villa rather than the champions.
But after digging deep, and finding inspiration from an untried teenager, United have leapfrogged Liverpool at the top of the table.
And they also avoided a third successive league defeat, which would have been more galling given that Villa were thumped 5-0 by Liverpool in their last match.
They struggled with an unfamiliar back four that was forced upon them because of Rio Ferdinand's injury and Nemanja Vidic's suspension.
Gary Neville, returning from injury, was brought in to partner John O'Shea in the heart of defence, but that proved to be a costly mistake.
Man Utd: Van der Sar, Neville, O'Shea, Evans, Evra, Nani (Macheda 61), Carrick, Fletcher, Ronaldo, Giggs, Tevez (Welbeck 87).
Booked: Macheda.
Goals: Ronaldo 14, 80, Macheda 90.
Aston Villa: Friedel, Luke Young, Cuellar, Davies, Shorey, Milner (Reo-Coker 76), Petrov, Barry, Ashley Young, Carew, Agbonlahor.
Booked: Milner, Ashley Young.
Goals: Carew 30, Agbonlahor 58.
Att: 75,409
Ref: Mike Riley (Yorkshire).
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