The Portuguese coach was appointed as the club’s new manager in the summer and has been tasked with steering the Red Devils back into the top four after their disappointing fifth-placed finish last season.
Herrera has been a regular fixture in the Manchester United first team this season and has made 20 Premier League appearances this term, notching up three assists.
And the Spaniard has revealed that Mourinho has been very clear in setting out his targets for his players this season.
Speaking to Manchester United’s website ahead of Sunday’s crunch clash with Leicester City, Herrera said: “I know what he wants from me.
“We have a clear relationship. I know what he expects from me and I will always try my best.
“I can make mistakes, as can any player, but the most important thing for me is the achievements of the club and the team.
“I think everyone knows in the club that I try to always give everything. Sometimes more successfully than other times but I try my best, always.”
Manchester United are currently in sixth place in the Premier League table and 14 points behind leaders Chelsea heading into this weekend’s round of games.
The Red Devils are aiming to bounce back to winning ways against Leicester City at the King Power Stadium on Sunday afternoon.
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