Manchester United's Henrikh Mkhitaryan has said former manager Jurgen Klopp played a key role in his psychological development as a footballer, and revealed how the German's advice helped him through a tough spell during their time together at Borussia Dortmund.

The Armenian's struggles with the mental aspects of the game have been plain to see this season, with the winger enduring a difficult start to life in the Premier League after moving to United for £26.3m in the summer.

The 28-year-old was notably substituted during his side's 2-1 defeat by Pep Guardiola's City in the first Manchester derby of the season last September.

Mkhitaryan's next league appearance came more than two months later as he struggled to recreate the sort of form that saw him emerge as one of the Bundesliga's top players prior to his move to England.

But the 28-year-old has since rediscovered his talent, notably scoring the winning goal against top-six rivals Tottenham late last year.

Speaking to the BBC, the winger revealed that Klopp offered him some important advice during their Dortmund days which has stuck with him ever since.

"I am thankful to Klopp. He worked on my personality and the psychological part," he said.

"At Dortmund, I was very stressed after a few games when we were playing really bad.

"Klopp showed me the way. He supported me and told me I had to keep my head up because good things were coming. He helped me to become a player."

Mkhitaryan played under Klopp for two seasons in the Bundesliga before the coach left for Liverpool in 2015, with the Armenian following him to the Premier League eight months later.

With five goals to his name from 11 games, the Armenia international is finally flourishing in England.

"They are both very friendly and very good at their jobs but the way they work is different," Mkhitaryan added of Klopp and Mourinho.

Henrikh Mkhitaryan has established himself in Jose Mourinho's starting XI (Getty)

"It is the first year under Jose's management and we are working very hard. He tells us what he wants to see. Of course, it is not very easy when you have a new manager.