Liverpool boss Benitez: Keegan's return can work at Newcastle
"As a player he was amazing and as a manager I think he is also a good manager," Benitez told liverpoolfc.tv.
"I have a lot of respect for him and wish him all the best for the rest of the season."
Benitez also gave his support to the idea of using sin bins in football, as a way of punishing sides without necessarily seeing them reduced to ten men for the rest of the match.
"It is funny because someone was talking to me about this recently, and he told me it could be a solution," he said.
"I think it is a good idea. It is something you would need to put into practice at another level and see if it is good, but it could be, why not?"