Enter Javier Hernandez. The Mexican scored twice and was the architect of a third as United overhauled Villa's two-goal advantage to extend their lead at the top to four points.
Defeat was desperately cruel on this young Villa side who had appeared set to record their first victory over United here since 1995 -- when Alan Hansen famously, fatefully, declared that nothing could be won with the kids in Alex Ferguson's side. Now the kids are in claret and blue and this was a harsh lesson for them.
With goals and confidence soaring prior to this encounter, United were soon into their groove -- a shot by Antonio Valencia blocked and a header from Michael Carrick plucked from under the crossbar by Brad Guzan -- spiced by boos from home fans for the returning Ashley Young who skimmed a low effort wide.
Villa grew in belief. Another attack and this time Christian Benteke was released, played onside by Patrice Evra only to dally and allow Rio Ferdinand to scamper back and block his shot. Stephen Ireland's clever positioning, in the middle of three behind the main striker, was causing United problems and he again collected possession, picking out Gabriel Agbonlahor only for his cross to evade Benteke.
Despite their perilous league plight, and dire previous record against United, Villa's young team were certainly not intimidated, with the tactics of manager Paul Lambert clear: inevitably cede a modicum of possession, soak up the pressure and hit their opponents hard on the counter-attack with the crucial Benteke proving a handful for the returning Chris Smalling who suffered a cut to his head and a bloodied shirt after fouling the Belgian.
It added to the sense that, with this game more than most, the first goal could be even more vital especially if Villa claimed it and Vlaar was alert to head clear as Robin van Persie shaped to finish and, then, Valencia struck a fierce angled shot over while Scholes was fortunate to escape, gaining a free-kick, as he lost possession under pressure from Ireland straight to Benteke in the United area.
The pattern appeared set with Villa, although entrenched at times, showing admirable determination to maintain their shape and harry their opponents -- as evidenced by Enda Stevens hunting down Valencia -- but also to play.
Villa gained their reward. As half-time beckoned Benteke, again, proved too powerful for Smalling -- simply bullying him down the Villa left and cutting the ball back to the onrushing Weimann who simply sidefooted his shot high into the net. It was too powerful for David De Gea and sparked wild scenes of celebration. Not least from Lambert. Yet again United were behind.
Ferguson had seen enough -- and hooked Young at half-time. United were quickly out of the blocks again, presumably stung by Ferguson's words at the interval but, incredibly, it was Villa who struck. And again it was Weimann.
What was remarkable was how United were carved open with Benteke's dummy, the ball running to Ireland who moved it on to Agbonlahor. He crossed low and Weimann turned it home from close range.
United had been two goals down here two years ago so they knew there was time. Scholes hit a quarterback's pass to Hernandez, on the shoulder of the Villa defence. The striker appeared to get the ball caught in his feet but nimbly adjusted to hold off Ciaran Clark and roll his shot through Guzan's legs to pull a goal back and change the mood.
Not that Villa were cowed. They also sensed goals and Benteke twisted to reach an Ireland cross only for De Gea to hold his header.
"Attack, attack," exhorted the United fans. And they did. Rooney found the overlapping Rafael and he crossed deep for Hernandez to volley back across only for the ball to cannon off Vlaar in the net.
Villa rallied with Bannan delivering a cross met by Weimann. His powerful header was surely going to complete a hat-trick? But, no. Superbly, De Gea pushed the ball out.
Still the chances flowed in a remarkable match with Van Persie rushing in to meet Rooney's corner to crash a header against the crossbar. The woodwork was still shaking when Van Persie then struck a powerful shot that again cannoned off the bar.
But United would not be denied. Van Persie swung in a free-kick and, somehow, Hernandez was not tracked by Stevens. It proved decisive. The striker stooped low to steer his header past Guzan and cap a remarkable comeback with United, once again, coming from behind.