Sissoko has already earned plenty of praise from Liverpool fans but Benitez says the best is still to come from the twenty year old.
"We had an advantage over Everton. I already knew the player. He had good memories of winning trophies with me at Valencia. We knew Everton were interested, but it was easy to sign him," said Benitez.
"As a defence, if you have Sissoko in front of you all the time, blocking and intercepting the passes, then maybe where last season you had ten balls to defend this season you only have four. He makes it easier for the defenders. It will be even better when Sissoko starts to learn about tactical movement.
"He has so much energy you wouldn't believe how much he runs during a game. Every game he runs more than 11-12km. One game, Crouch ran more than him, but normally it is Sissoko who runs most. It depends on the position, but most of the other players run 8-10km, midfielders maybe a little bit more.
"We spoke to him about the style of football in England, about the referees and opponents. He has the qualities that we were looking for, so when we heard he was available we had to sign him.
"With time, Sissoko can become a much better player but I don't want to put him under any pressure now. Momo is a player who can work for 90 minutes every game. He is improving every day, every training session.
"In one or two years he will have more experience and he will be a fantastic player and a key player for us."