Mourinho's men travelled to the London Stadium on Saturday boasting an enviable record against West Ham but came away chastened after a 3-1 defeat killed off any realistic hopes of a Premier League challenge before the end of September.
He explained to the Daily Mail: "The muddled tactics were exposed by West Ham's third goal".
They also claim Mourinho has been given a week to turn his misery start to the season around.
And it was another tough day at the office for him, summed up by him passing the blame in his post-match press conference.
By the time West Ham took the lead in the fifth minute, United had struggled to escape its own half.
Instead, Issa Diop and Fabian Balbuena's partnership at the back continues to blossom. There was no coherent offensive strategy as they sleepwalked to a defeat that looked on the cards from the moment Felipe Anderson scored his maiden goal for the club. A corner was headed on by Issa Diop and Yarmolenko took the ball past Nemanja Matic before a shot took a heavy deflection off Victor Lindelof and looped into the net.
Mourinho is under severe pressure after another abject display at the weekend saw Manchester United lose 3-1 to West Ham in the Premier League.
Remember when Jose Mourinho said there was "no problem" with Paul Pogba? No was the answer.
Mourinho was the centre of attention after the match, with his future being speculated upon by the pundits in the wake of the West Ham match. But the Austrian is back in full form.
Pogba combined with Fred to help the Brazil worldwide scored his first Premier League goal to break the deadlock. That is 10 points, with 10 goals for and 12 against.
Everyone is playing for the badge and this is summed up by this picture.
Most importantly of all, West Ham are showing great team spirit.