John Carver's side lost 3-0 to the Toffees at the weekend and the Dutch international says the whole squad have had a conversation to make sure they do not perform poorly again.
Janmaat says that Newcastle's performance will be improved in their next game against Arsenal because if they don't raise their game they have 'no chance' of getting a result.
“We spoke after the game and there is a determination to make sure we do not repeat what happened against Everton,” Janmaat said. “I thought we were better with ten men than we were with 11, and that should not be the case.
“The energy was not high enough, and the performance was simply not good enough all round. We have to play much better in the next game to have any chance of getting a result. If we play in the same way against Arsenal, we will have no chance of doing anything."
Newcastle have failed to perform in a number of games this season, so the squad having a frank conversation can only be a good thing.
Too often, especially away from home, the side have seemingly resigned themselves to defeat before kick-off and there has been a lack of application.
It means there have been a number of inexcusable performances and the feeling around St. James' Park is one of frustration.
The Magpies' season appears to be petering out into mediocrity once again and it is hard to see how Newcastle will break out of their slumber unless the players' conversation after the Everton game has the desired impact and raises their performance levels considerably.