Two goals in stoppage time set the end game into overdrive for Ole Gunnar Solskjaer.
One scored by Joao Pedro, a shot driven low through the legs of David de Gea after Antony Martial had lost another challenge with a shrug.
The other a punt by Ben Foster, poorly defended by Nemanja Matic who ducked out of a header while deputising at centre half, and smashed in by Emmanuel Dennis.
Manchester United's woeful performance at Watford led to Ole Gunnar Solskjaer's departure
Two goals to encapsulate the shambles that had gone before and turn a dreadful result into a total horror show. Solskjaer was toast and he knew it. That comes with the territory.
For all the admirable loyalty to a legend, Manchester United are not supposed to fall into disarray at places like Watford any more than they supposed to be battered by arch-enemy Liverpool at Old Trafford or yield quite so readily to the clear superiority of neighbours Manchester City.
So Solskjaer is out and now what? Will we see a bounce from happier players and a flicker of better times ahead before the familiar problems reappear, as another man tries to improve the defence while satisfying United’s demand for flair?
Two late goals, including one from Joao Pedro, meant that it was a horror show for United
This elusive balance, so tantalisingly close at times under Solskjaer, as it was at times under Jose Mourinho, has disappeared again.
Watford, on Saturday, was an extreme example.
United were soft in the middle, where Scott McTominay and Matic never got to grips with the trio of Moussa Sissoko, Tom Cleverley and Imran Louza.
There was little by way of help from the front four. When Bruno Fernandes ventured back to defend, early in the game, his miscued volley landed his back four in trouble and led to a penalty, twice taken by Ismaila Sarr and twice saved by De Gea, which set the tone
