A big defeat requires a big response and defeats don't get much bigger than a humiliation at the hands of your local neighbours.
While conceding six to Manchester City is nowhere near as much of a shock or as momentous as it was over a decade ago, Manchester United simply can't take a defeat like that lying down.
Only a returning Antony Martial eager to get amongst the goals and a Blues backline that had switched off saved them any face on Sunday, with a 6-3 defeat an extremely flattering scoreline for the visitors.
Erik ten Hag has had to quickly get used to the sour taste of embarrassment as United boss but the last time his side went in at half-time 4-0 down - just a few weeks back and in far more shocking fashion at Brentford - it did have its benefits in the aftermath.