The Dutchman believes Aguero is now inside the best five strikers in the world.
He said, "He's working a lot harder from the time where he was a little bit off, he did do things less than he's doing now. He's helping the team, coming back from the striker's position, scoring goals against big teams which is very important for a striker.
"With form like this in one of the biggest competitions in the world, scoring as many goals and the quality of goals you're for sure in the top five strikers in the world.
"I think he's now in the perfect situation with Manchester City."