After an uninspiring performance and disappointing result against Brighton last week, Mourinho demanded a response from his players as Manchester United traveled to West Ham United.
A victory was crucial to building some momentum going into next week's FA Cup final against Chelsea. He decided to ring the changes and Alexis Sanchez, Jesse Lingard, Scott McTominay, Ander Herrera and Luke Shaw all started the game.
Despite the first-half being a duel of good tempo, both teams had to settle for half chances, with Adrian being the busier goalkeeper, making five saves.
Luke Shaw came closest for the visitors when he struck the post and both teams were waiting for a spark from somewhere.
However, the tempo died down completely in the second-half and United seemed to be happy to take a point away from the match.
United thus secured the second spot in the league this season and de Gea won his first ever Golden Glove after his 18th clean sheet.
We look at three things that went wrong for United on the night.
#3 Lack of intensity in the second-half
Despite the game ending 0-0, the first half-an-hour looked nothing like it. Both teams looked to take the game to their opponent and carved out decent openings.
But, if one expected more or less the same in the second half, they would have been disappointed, to say the least. The intensity, tempo and desire reached a new low and Jose Mourinho failed to ring the changes at the right time.
United hardly troubled Adrian in the second 45 minutes and for the most part of the match, they looked content with coming away with a point.
#2 No answer to West Ham's man-marking
West Ham defended brilliantly on the night. Young Declan Rice put in a great shift as he nullified Sanchez to a large extent.
United started with Sanchez and Jesse Lingard up top and both of them looked to come close, drop deep, get the ball from the midfield areas and initiate attacks.
This made life easier for West Ham's defenders as they were able to outnumber the United players easily.
United rarely had enough numbers inside the box to trouble Adrian and they lacked serious quality in the final third.
The home side forced United to play in tight quarters and used this as an excuse to stifle them and deny them any space to operate.
#1 Lack of a proper No. 9
Another game without Romelu Lukaku and another game that proves the underlying difference he makes when he plays.
Mourinho's decision to field a team without a proper striker back-fired and as mentioned earlier, both Lingard and Sanchez looked to drop deep instead of running behind the defenders and stretching them.
This lack of running off the ball and into the box was rarely executed and as a result, their midfield trio often had to stay glued to their formation and thus negated the influence Pogba makes with his marauding runs into the box.
This forced them to play at such narrow spaces and operate very tightly. West Ham players easily outnumbered their counterparts in this aspect and despite the visitors having 16 shots on goal, all of them either went off target or were easy enough for Adrian to deal with.
Mourinho will want Lukaku fit for the FA Cup final at any cost after witnessing this display from the players he fielded tonight.