The former Liverpool midfield man is convinced that Chelsea fans will quickly get over their hatred for Benitez and become fans.
"Chelsea fans bristling at the idea that Rafa Benitez is their new manager: get over it and enjoy the success that will come your way," said Hamann.
"You can question the decision to sack Roberto Di Matteo, you can question Roman Abramovich's motives.
"But I simply don't understand how you could question the appointment of Chelsea's ninth manager in eight years.
"Chelsea supporters are probably bitter that their new boss is a manager who twice denied them a place in the Champions League final - each time with an inferior side.
"What Blues fans need to appreciate is that Benitez is a man who will improve Chelsea," claimed Hamann.
"I had a great working relationship at Liverpool with Benitez, who I regarded as a meticulous student of his own players and tactics but also those of the opposition.
"I found him open and honest. You knew who was in charge and you knew when you were wrong but it was a healthy relationship. I don't think there are many more knowledgeable people in the game."