The midfielder now has eight senior starts under his belt since arriving on the scene.
When asked if Longstaff will be able to continue his excellent displays, Benitez told the Evening Chronicle: "Talking with Sean he is fine and he is mature enough.
"He is somebody who will continue to get better because he listens to you and works hard. He's very humble.
"We'll see with the others back regarding competition but in terms on his behaviour and what he will do next I am quite positive that he'll do well."