The Red Devils go into the game having won back-to-back matches for the first time in 2014, and Mata believes that the team's confidence and morale have been boosted by their recent form.
"The team has got confidence and now there is an exciting challenge ahead: our derby against City on Tuesday," Mata wrote in his blog.
"It will be the first one for me and I'm looking forward to it. You can already feel in the streets that special atmosphere. Our morale has been boosted ahead of the next games. I think it is vital to remain mentally strong and focused on our goals.
"That is how we are going to approach to the last stage of the Premiership. As if every game was a final. Next weekend we will play in Old Trafford again, this time Aston Villa. We must get better results at home."
United could leapfrog Everton into sixth place with a win, although they have played one more game than the Toffees.