Benítez has initially only been given the job at Stamford Bridge until the end of the season, but Hamann is confident Chelsea can win title with him in charge.
"If Rafa is at Chelsea for a couple of seasons I can guarantee they will win the title," he told the Telegraph. "I think they may well win it this season because he is taking over a squad which already has some excellent players.
"It's a really good squad and that will suit him. It is the perfect situation for him. It's an excellent appointment, regardless of how long he has been given at this stage.
"The players at Chelsea have, perhaps, had a little too much to say, but they have a strong manager who will take control. They are a group of who have had some fantastic success, but that is in the past and they need to focus on what they want to achieve going forward."