"People are saying Frank is not at his best because he hasn't scored a couple of goals. He is still getting in the right positions and is still getting the chances and he is desperate to score," said the Liverpool skipper.
"I am sure a goal is only around the corner and if a couple of Frank's chances had gone in, everyone would be saying how well he is doing. There is that fine line between not scoring and scoring.
"I think scoring goals gives you confidence and because Frank has scored so many goals for Chelsea and England over the last couple of years, because he hasn't scored in this competition he is maybe doubting himself.
"But he has set himself such high standards that if he doesn't score for a couple of games, people are going to question him. We know he is going to score an important goal for us so hopefully it will be on Saturday. His all-round play has been good. We are happy with that."