The 28-year-old has played just 90 minutes of Premier League football thus far this campaign, but was praised by Mourinho for his 13-minute cameo during the win over Everton.
Manager Jose Mourinho was also happy with the striker's performance after the Red Devils thrashed Everton 4-0 at the Old Trafford.
The Armenia worldwide has been widely praised for his superb performance at the match after netting the game's second goal in the Old Trafford rout.
"We should have been winning by at least two goals but you know when you play against Everton you are going to suffer".
The visitors produced a solid display for much of the Premier League match, particularly in the second half when they were only denied an equaliser thanks to the heroics of David De Gea. Interestingly, three of Manchester United's goals came towards the end in the final ten minutes of the contest.
United will head into that game buoyed by their showing against Everton.More news: Hurricane Irma: prayers for Barbuda at Southwark Cathedral service
"It's been an intense and happy week for the Manchester United family, with two games and two convincing wins at Old Trafford, feeling the extraordinary support from our fans and without conceding a goal", Mata said in his blog.
Manchester United took the lead in the fourth minute via a stunning goal by Antonio Valencia which is sure to be a contender for the goal of the season.
"Everton had a reaction in the second half, we lost a little bit of control". So, it's even more hard and even more important.
In an article of its own, Express says Mkhitaryan, alongside Valencia and Lukaku shone against Everton.
"It is more hard when you are sleeping".
He said: "You saw the team growing in confidence, in quality".