"I didn't know him but in the summer [Emery] called me to find out about the team and the club, for a bit more info," he posted to Twitter.
"It's normal to speak to someone who has been inside for their view. I told him what I thought: the things that he had to change and the things he had to reinforce.
"I can't say that [what they were]. That's a secret. But I was clear, direct: I said that it was an incredible club, that had everything it needed to win, but that there were things that had to change. I said it would be hard to change some of them.
"Arsene was there for 23 years and changing 23 years overnight … it needs time. It's an opportunity for [Emery] to take a club like Arsenal and try to make them champions which is what I want and what all Gunners want. I think they have chosen well."