The North-East outfit are currently rooted to the bottom of the table, seven points adrift of safety.
"We need to send out the right message, that we are not down yet, that we still have games to go and we have to believe," the Shields Gazette quotes Poyet as saying.
"We just have to forget our position and concentrate on playing the game this weekend. I think that's vital."
The Black Cats will take on Everton at the Stadium of Light on Saturday.