Arsene Wenger admits it makes him "angry" to see Harry Kane playing for Tottenham rather than Arsenal.
The England international spent a year with the Gunners as a youngster before leaving the club and ultimately signing for Spurs at the age of 11.
Wenger was not aware of Kane's Arsenal past until earlier this week but concedes it will be frustrating to see him line up for the opposition at the Emirates Stadium on Sunday.
"I didn't know that [Kane was at Arsenal] until I read it in the papers," he said.
"I found it quite funny, you know, but you are always a bit angry as well because I asked - why did he go?
"But at nine years of age, boys can move here and there. Some people move from Tottenham to Arsenal. At youth level, because their parents find a different job, they often move somewhere else.
"How good can he be, I don't know. I don't know who you could compare him with but I think he can be a top player. He has top qualities and I think he will make a great career."
Wenger ruled out the prospect of attempting to bring Kane back to Arsenal, however, now that he is established as a Tottenham favourite.
"Once a player is at Spurs you do not even consider him anymore to be on your radar because you do not historically have many transfers from one club to the other," he added.
