Diame said last week that he had fallen short of his own expectations since moving from Hull to Newcastle last summer.
However, Benitez has defended the 29-year-old, by suggesting that he was being far too hard on himself.
“I said to him he was too honest when he said about him sleeping too much since he’s been here,” Benitez said.
“Sometimes players, media Press and fans think the players have to score goals, but sometimes it’s just about working hard and getting to the level that you know they have.”
Diame has proven to be an effective player in both the Premier League and the Championship during his time in England to date.
The powerful midfielder appears to be back to his best for Newcastle now, too.
Diame was excellent as Newcastle picked up a 4-0 victory over Birmingham City at the weekend.
Newcastle’s victory over the Blues has lifted them back up to the top of the Championship table.
The Magpies are next in action on Wednesday evening, when they take on Wigan Athletic at the DW Stadium.