As it stands, Simeone's side sit top of La Liga due to their superior head-to-head record over Real Madrid, who are also in action this evening against Seville.
"The game against Granada will be difficult, complicated, because our opponents need the points and so do we," he told reporters at a press conference.
"We'll need a high level of intensity to take the game the way we want. Hopefully the stadium will be full. That's the only thing that concerns me at the moment.
"I hope the fans understand that we need them. I invite everyone to come to the stadium and get behind the team. We need a great effort from us and from the fans."
Fellow title rivals Barcelona, meanwhile, host Celta Vigo at the Camp Nou tonight.