Ozil, who was dropped for the game, has since been suffering back spasms which ruled him out of the Europa League clash against Vorskla Poltava, Sunday's win over Tottenham and Wednesday night's 2-2 draw at Manchester United.
United's goal difference is -1, having allowed 25 goals and scored 24, and Mourinho cited this.
United are 18 points behind league leaders Manchester City and eight behind the Champions League places.
Jose Mourinho is staying at Manchester United and the club are happy with his work, according to his agent Jorge Mendes, the influential deal-maker who controls so many of football's biggest names.
The Red Devils are struggling to score goals, too, given the well-documented struggles of marquee signings Romelu Lukaku and Alexis Sanchez over the past 12 months.
The United manager is full of respect for new Fulham manager Claudio Ranieri, the man he replaced when taking his first English job at Chelsea in 2004.More news: US Senate introduces resolution accusing MBS for Khashoggi murder
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Former England defender Ferdinand admitted that Manchester United are a long way behind their traditional rivals in the top-four race.
"We pressed the ball more, we gave difficulties to Arsenal, we were fast in our transitions, so we had that spirit, we had that mentality that brought our game to a good level, to a better level".
"Everyone else is in the chasing pack".
"So that's something to build on. We're going to look when he can come with us".
"The game is not going to be 11 against 0, it's going to be 11 against 11, good players in the other side, I repeat that the position, the points sometimes don't say much about the real potential of the team".