Pep Guardiola's side will win the league eventually but Mourinho will do everything in his power to make sure that his United side doesn't let it happen against them given how much it would hurt, since they are their biggest rivals.
United are having a decent season as they sit in second spot in the league but they are still sixteen points City going into this game which shows how good their noisy neighbours have been.
United looking to delay City title celebrations
The problem that United have though is that under Mourinho, United's away record against the other top six sides isn't the best but this weekend would be a good time to put things right.
United come into this game on the back of a 2-0 win at home last weekend against Swansea City, with the goals being scored by Romelu Lukaku and Alexis Sanchez.
City looking to bounce back after heavy European defeat
On the other hand, City have only lost one game in the league all season against Liverpool in January and after they defeated Everton 3-1 at Goodison Park last weekend, they now have the opportunity to wrap up the title with a win this weekend.
That means they will want to put things right this weekend as their players will want to show that they are better than what they showed against Jurgen Klopp's men.
City looking to seal title with double over their Manchester rivals
City will also be confident going into the game giving the fact that they defeated their main rivals at Old Trafford in December.
Guardiola's men won the game 2-1 with the goals being scored by David Silva and Nicolas Otamendi, while Marcus Rashford netted for United.
Guardiola has confirmed that Sergio Aguero will have a late fitness test ahead of the game after taking part in light training on Friday.
That means that only Benjamin Mendy, who is recovering from a serious knee injury, is the only person who is confirmed to miss the game for City tomorrow as they look to try and win the league.
Mourinho provided a very positive update on the injury situation at his pre-match press conference as he confirmed that Phil Jones and Daley Blind have both returned to full training after a couple of months out injured.
Ander Herrera and Marcos Rojo have also returned which means that Sergio Romero is the only player on the treatment table for United going into this game which is positive given how important the rest of the games are this season.
Referee: Martin Atkinson