The Rojiblancos boss believes his side's title tilt hinges on a series of positive results and has backed Diego Costa to come good for Spain.
The capital club is currently third in the Primera Division standings, just three points off leaders Real Madrid following a 2-2 draw with Carlo Ancelotti's side on the back of a costly 3-0 loss to Osasuna.
And, when asked whether it could do anything but win against Celta on Saturday, the Argentine replied: "Clearly, the last two outings have hurt our chances.
"Celta are a team with a lot of variety. They have a lot of possession. If we start the game, we will have our chances and that's what we have to do. We believe in the team and the group we have. There are guys who didn't play against Real Madrid. Hopefully we can have a great game and play as a team."
Diego Costa had a difficult debut for his adopted nation of Spain, but Simeone is confident his star striker will be able to make an impact for la Roja.
"Diego has ideal characteristics for any team," he said. "The trainers of the national team always follow us."