United looked set to take all three points from the Gunners at Old Trafford before Juan Mata’s opener was cancelled out by a late Olivier Giroud header.
It prompted Mourinho to brand his side the “unluckiest” in the Premier League.
But following the draw with their fierce rivals, which saw Ander Herrera take a lot of the plaudits from fans, Mourinho seemed resilient that the draw marked a turning point in their season.
And he took to Instagram with a motivational post for the supporters.
The Portuguese coach revealed that he received a phone call from Diego Maradona after the match.
Describing the Argentinian legend as “King Diego,” Mourinho thanked the Napoli legend before turning his attention to the week ahead.
He said: “After a great performance but a bad result I had a phone call from King Diego.. gracias Amigo, With you, my family, my other friends, my players and United is amazing.
“Supporters… Monday I will be ready again!!!”
Mourinho’s side are back in European action on Thursday night as they host Feyenoord in the Europa League.
A win would see them jump above their Dutch rivals in Group A.