After a slow start to the last campaign, Mkhitaryan emerged as one of United's key performers in the Europa League, a competition which the Old Trafford outfit went on to win in May.
The Armenian playmaker did not always produce in England's top flight but after already contributing one goal and five assists in half-a-dozen league contests, Mkhitaryan is confident that he is continuing to develop his game.
The 28-year-old told reporters: "I think that was last season. This season is different.
"I am working very hard in training, to be ready for Premier League games. I have started the season well and I am doing my best to help the team."
Mkhitaryan is expected to feature when United face CSKA Moscow in Russia on Wednesday night.