Sunday's 3-1 setback at Watford extended United's losing sequence to three games, while Mourinho also faced a backlash from supporters for not substituting captain Wayne Rooney after a below-par display at Vicarage Road.
However, after watching his side get back to winning ways against Northampton Town in the EFL Cup, Mourinho responded by claiming that the sport is full of "football Einsteins".
The 53-year-old told MUTV:: "I know that some football Einsteins - football is full of Einsteins - I know that they tried to delete 16 years of my career.
"They tried to delete an unbelievable history of Man United football club and to focus on a bad week with three bad results. But that's the new football - it's full of Einsteins.
"I can understand clearly the disappointment if the fans are disappointed with the last week. I understand completely, but I'm sure that with the team going back home [against Premier League champions Leicester City on Saturday] they will be behind the team like they always are."
United currently sit in seventh place in the Premier League table.