Hleb was in the last Arsenal team which faced Milan in 2008.
Asked about Arsenal's problems this season, Hleb told TMW: "Difficult to explain, but certainly if you start the season with some players who want to go, it is not the best, because the team has a bit of pressure.
"Alexis Sanchez wanted to leave, time was wasted. They must wait now for (Pierre-Emerick) Aubameyang to adapt to a new championship."
On Arsene Wenger, Hleb says his old manager has struggled as stars have left.
"It's all a question of titles, everybody wants to win, but they forget that every year Wenger loses important players and it is a continuous rebuild.
"He is a capable coach who deserves time and confidence and for me he is the best ever."
"I remember it very well, it's true, it could be my stadium, Inter my team. Working with Mourinho was certainly interesting, and today I cannot explain why I did not go to Inter, but I did not have the right mind at the time, I did not think like an adult."
As for his future, Hleb adds: "Tomorrow I'll fly to London and sign again for Arsenal (laughs). Seriously now I'm taking a break but it's clear that I still feel like a footballer, so I will evaluate the offers."