Zenit St Petersburg boss Dick Advocaat has is calling Sir Alex Ferguson the best manager in the world.
He said: "He's not just the top manager in Europe, he's top of the world.
"You can't work at that level and stay with one club for so long if you do not have exceptional qualities, it is so difficult.
"So, for me, he is the best manager in the world and the one everyone else has to look up to.
"I know Sir Alex but I haven't played against him, so I am looking forward to the game which I know will be very difficult."