The delusions of grandeur behind this logic are almost too many to number.
The idea that the same rabble that staggered to six defeats in eight matches can suddenly elevate their game to the level required to break those winning machines from over the road is almost endearing. It's rather like listening to that granddad who insists he could've been a contender - had he wanted to.This absurd, non-dilemma not only insults their opponents, but also the intelligence of anyone who's suffered the misfortune of sitting through United's recent defeats.
Tanking is hardly a sensible motivational tool in any team-building exercise. If City administer a shellacking - a distinct possibility in light of recent results - how would it help anyone associated with United? The best will flee first. David de Gea and Paul Pogba are unlikely to countenance a Europa League campaign at this stage of their careers. They'll be off. Others will follow, but for heavily discounted fees as United cut their losses.
Beating City in the Manchester Derby, on the other hand, means something. Finishing in the top four means something. Never"tanking" in a professional fixture, whatever the opponents or permutations, means something.