Cuellar insists the mood has not been dampened by defeat to Manchester City.
"The confidence in the team is very high," said the Spaniard, who will be playing in his first North East derby.
"When you lose everyone is unhappy but if you look at the table and you look at the games we have played before that you don't have to be scared or lose any confidence because the team is doing very well.
"You have to learn from your mistakes, but in Spain we say you cannot take your skin off just because you make a mistake or lose a game.
"We were doing so well before and when you make a mistake you have to learn from it and make sure you don't do it again.
"Because we're playing Newcastle next we don't have to prepare too much.
"We'll all be ready and waiting for the game."