When the noisy neighbours are "screaming" there are two things you can do. Stick your fingers in your ears in the hope of blocking it out, or fight fire with fire and take your own volume up a couple of notches. At the Etihad in May, Sir Alex Ferguson took the first option. The selection of Ji-sung Park - starting a Premier League game for the first time since January - ahead of Antonio Valencia was the clearest sign of that. Though Park rarely let Ferguson down, Valencia had been one of his shining lights and surely deserved a starting spot for the biggest game of the season?
Of course hindsight - and the fact Joe Hart could have lit a cigar at the first whistle and barely been disturbed in the 90 minutes that followed - says yes. Suitably chastened, on his next trip across town Ferguson reverted to type, the oldest gunslinger in town reverting to the 'you score six, we'll score seven' mentality that has served him so well down the years. Valencia in from the start, Tom Cleverley back in the side just days after hobbling off against Cluj through injury and ignoring what must have been a real temptation to throw one of his trusted lieutenants - Paul Scholes or Ryan Giggs - in. To pick either would have been a mistake.
It was the team most United fans would have gone with. And though City had much the better of the opening exchanges, as is to be expected of a home side, they did not have to wait too long for it to bear fruit. Sixteen minutes in United put operation counter-attack into play. Fifteen seconds, 10 touches and from Patrice Evra at left-back, the ball had found its way via Robin van Persie, Ashley Young and Wayne Rooney to the bottom corner of the Manchester City net. Just before the half-hour they came again, this time down the right. Valencia linked with Rafael, one of United's stand-out players so far this season, and the Brazilian crossed for Rooney to slide home the second.
United have mastered the art of winning when not playing well - the mark of champions, we're told - but this was counter punching of the highest order. It was nothing new. Fielding two wingers, soaking up pressure and hitting quickly and devastatingly, Ferguson had merely gone back to the future. Young, enjoying one of his better games for United, netted a third just short of the hour mark only to be denied by an incorrect offside flag. That City would score almost immediately merely added insult to injury. Then when Pablo Zabaleta pulled City level they looked the likelier winners. United did not sit back and take their punishment, though.
Forward they came. Danny Welbeck forced a mistake from Gael Clichy, Rafael drew a foul from Carlos Tevez and Van Persie did the rest, aided in no small part by former Arsenal team-mate Samir Nasri in the wall. Fortune played its part, of course, but United supporters will rightly wonder how things would have turned out had Young's goal stood.
"That is immaterial now, of course, and United approach Christmas with a six-point lead at the top of the Premier League. Having thrown away a bigger advantage at a much later stage in the season so recently, there will surely be no complacency in the camp."
But there are still some decisions for Ferguson to take. He must decide on his first-choice goalkeeper - and stick with him. It can be no coincidence that David de Gea's best form for the Red Devils came when Anders Lindegaard was injured. Virtually assured of his place, the young Spaniard was not casting anxious glances over to the bench if he made a mistake. For a man who has regularly stressed the importance of a settled back five, Ferguson is doing neither man any favours with his rotation policy. Lindegaard provides a solid back-up option, but De Gea - who showed his class at the Etihad with a quite magnificent double save just before Toure's goal - should now be number one for an extended period.
Ferguson's other headache has long been discussed - midfield. With Nani appearing to be on his way out, Valencia and Young made compelling cases at the Etihad for the two wing roles. Centrally, Cleverley and Michael Carrick certainly didn't let Ferguson down. Cleverley's form this season has been fitful at best but though his passing and decision-making aren't yet as good as theirs, his obvious mobility brings a dimension to the United midfield that Giggs and Scholes can't. Carrick is something of a Mr Marmite in the eyes of United fans - some love his composed, simple passing game while others think he's not in the class of Roy Keane as a defensive midfielder or Scholes as an attacking threat. But he plays a key role in breaking up attacks and setting United going. Given the world-class talents the Red Devils have had in their midfield down the years, though, you can perhaps understand why some don't 'get' him.
My view is he has suffered more than anyone from the virtually constant rotation of midfield partners alongside him - Cleverley, Giggs, Scholes, Anderson and Darren Fletcher having played in that role already this season. Whether Ferguson looks to the market - Dutch schemer Wesley Sneijder is again being linked with United - remains to be seen, but while his current options are fine domestically, they are likely to be found wanting in Europe. Regaining the Premier League title will suffice for the United fans this season, though, and Sunday shows going back to the future provides the route to glory.