Arsene Wenger admits it is difficult for him to see Robin van Persie in any shirt other than Arsenal's.
Wenger will come up against the Dutchman once again on Sunday when the Premier League leaders face Manchester United at Old Trafford.
Although it is more than a year since he sold Van Persie to Sir Alex Ferguson for £24million, Wenger says it does not sit well with him to see the striker in United's kit.
Van Persie's first season at Old Trafford ended with a first Premier League winners' medal, eight years after Wenger brought him to England from Feyenoord.
"Of course it's strange because for me he is an Arsenal man," Wenger said.
"I took him when he was a very, very young player. We have gone together through very difficult periods and he became a world-class player and for me he is an Arsenal player."
Wenger also revealed it was former United coach Rene Meulensteen who was vital in influencing van Persie to make the move north.