Benitez says confidence, self-belief and a changing role have contributed to the resurgence of a player who had looked set for a January move.
"It's the little things that make the difference," said Benitez. "I know Fernando is playing a lot of games but he has more confidence now and is scoring goals.
"We've told him to go high around the box rather than go too deep when we are in possession, because we have players like Hazard and Oscar who can work behind him.
"Fernando understands and is trying to do that. He's a player who can run behind defenders - all he has to do is what he is used to doing. He was always trying hard. Maybe now he is trying hard in the right position."