Arsène Wenger believes Mathieu Flamini has reached a new level since leaving Arsenal in 2008.
The French midfielder began his second spell under Wenger when he signed late in the transfer window and has slotted seamlessly into his old position in front of the back four.
Flamini told Arsenal Player that the five years he spent at AC Milan helped him "evolve" as a footballer and Wenger agrees.
"Yes [he has improved tactically] because in Italy it's more all calculated," said the manager. "In England it's more drive and enthusiasm. He has a good mixture.
"He wanted to come back because he missed the way we play. It didn't create any big headlines when he came back but I always feel the best way to make headlines is the quality of your display because people will notice.
"He integrated very well into the spirit, the solidarity and the hunger of the team. And he accepts [the need] to have a real team attitude, something that I find quite normal. That is of course very important for the success of any team."