The fury from the away end was not aimed in any particular direction but the message was clear - this is not good enough and we must improve.
The Blues are in danger of replacing United as the crisis club in the Premier League. Pochettino answered questions about Erik ten Hag’s future before the game but he is now under the spotlight.
Chelsea’s support was brilliant throughout, but they let their team have it at the final whistle. Players applauding the away end were met with boos, and some left early to head back to London.
This performance was arguably worse than the collapse at Newcastle two weeks ago, but instead of digging out his players like he did at St James’ Park, Pochettino protected them.
“Of course we need to improve in our position in the table,” he said. “At the same time there is the reality that we performed well until Newcastle and we did not get what we deserve. Of course, Newcastle and today, I think the result is fair.
"The message was clear from a furious away end - this is not good enough and we must improve"
“[I am] not worried because there are too many circumstances that you need to put why we did not perform. To play against Brighton with one less for 60 minutes, I think maybe affects a little bit the energy and the performances of the players.
“Then too many players injured, we need to recover them as soon as possible to be more competitive and to have options and to help the team achieve what we want.
“One day more for Manchester United to prepare the game. I am not disappointed because [my players] gave everything.”
Pochettino’s words sounded like they could have come from Graham Potter last season, but they fall apart when under scrutiny.
United arguably had more reason to be tired, having played in the Champions League last week. But Chelsea played with 10 men for the whole of the second half against Brighton on Sunday only because Conor Gallagher made two poor challenges.
A lacklustre Chelsea were bombarded with 28 shots on Wednesday night, including a Bruno Fernandes penalty saved in the first half.
They gave more chances away over 90 minutes than any Premier League team this season, excluding nine-man Spurs when they imploded against the Blues last month.
Early United pressure was rewarded when Scott McTominay broke the deadlock with an instinctive finish.
Against the run of play, Cole Palmer equalised just before half-time after goalkeeper Robert Sanchez, the only respectable Chelsea performer on the night, kept them in the game.
Pochettino made a change at half-time by bringing on captain Reece James, who was nursing a minor knee issue, for a poor Marc Cucurella at right-back, but he provided only a minor uplift.
McTominay deservedly headed United back in front in the 69th minute. Pochettino had been preparing defender Ian Maatsen to come on for one of his forwards in a bid to shut up shop as the goal went in.
Maatsen was then told to sit down before Pochettino decided to roll the dice by bringing on Armando Broja, who headed a late chance against the bar.
Nicolas Jackson squandered a close-range header, while Enzo Fernandez could have got on the end of two crosses but, in truth, Chelsea would not have deserved a point.
Chelsea had looked resurgent after beating Spurs and then drawing with Manchester City before the international break.
It now feels like they are back at square one, having accumulated fewer points than they did at this stage last season.
Next up on Sunday is a trip to Everton. More excuses will not cut it, with Chelsea languishing in 10th place and Champions League qualification looking an increasingly remote prospect.