Usually a member of the Arsenal coaching staff would stay late to provide service for the likes of Pierre-Emerick Aubameyang and Alexandre Lacazette.
But recently Mkhitaryan has decided to take on that role.
It was claimed Mkhitaryan was helped the Gunners stickers with extra practice.
And Arsenal manager Arsene Wenger confirmed these reports during his press conference ahead of the north London derby on Saturday.
"He has a very professional attitude and overall I think that is what you want from every player,” said Wenger.
“I am not surprised about that because I find that absolutely normal."
Mkhitaryan signed for Arsenal from Manchester United last month as part of a swap deal with Alexis Sanchez.
The Armenian made a strong first impression on his home debut in Arsenal’s 5-1 thrashing of Everton by recording three assists and establishing a very successful connection with new record signing Aubameyang, who he previously played with at Borussia Dortmund.
Wenger was full of praise for his new No 7 and recently compared Mkhitaryan to fan favourite Santi Cazorla, saying that just like the Spaniard, Mkhitaryan is fuelled by a love of playing football.
"There are similarities there," said the Arsenal boss.
"Santi was an exceptional football player. I met Mkhitaryan before [he joined Manchester United] and I always liked his game.
"He's a player dedicated totally. He comes from a country where you need special character to become a great football player. He looks happy to play football because he just loves it."