Hazard was an integral part of the Blues' blistering start to the season, which saw them pick up 22 out of a possible 24 points from their opening eight Premier League matches.
However, as the reigning European champions' form has slumped, so has that of the Belgium international, and Benitez knows he is capable of much more.
"He is great talent, but he has to adapt to Premier League tempo," he told L'Equipe
"I have seen him growing and he is better nowadays. He can change an encounter, what he has achieved is quite fine so far. But he can do much better."
The interim boss, who has come under much scrutiny since his surprise appointment at Stamford Bridge, has been using his contacts to understand his players and try to turn around the club's fortunes.
"I talked with him but also with Lille's coach Rudi Garcia that I know very well. I have a lot of information about Eden," he added.
"At Lille, he knew he was the key player and he played with that feeling 'I am the best, everything will be fine.' But when you go to a club like Chelsea, which plays in Premier League and Champions League, you always have to be at your best. That is something he will learn."