"I have a lot of confidence in Sami," Benitez told liverpoolfc.tv. "He is a fantastic professional so I knew he would play really well.
"Clearly, when you talk about Sami you are talking about a player who has been here for a long time.
"Everybody knows he is a nice lad, a very good professional and a very good player, so we are really pleased to keep him here.
"We have very good centre-backs here and it is good to see all of them competing for a place. That can only be good for the team."