Atletico must take on Osasuna on Tuesday before travelling to the Santiago Bernabeu for the first time since beating their rivals at their own ground in the Copa del Rey final in May.
But Simeone believes his side, who have made a 100 per cent start to the new season, could struggle against Javi Gracia’s men if their minds are not focused on the job at hand.
“We have to take each game as it comes, otherwise we’ll undo the good work done in beating Real Valladolid away from home,” he said.
“If we didn’t get a good result at home, that wouldn’t be good. We have to take each game as it comes and keep growing.”
Simone is not taking Osasuna, who picked up their first points of the season on Friday lightly saying:
“They’re a side that are dangerous out wide, with Emiliano Armenteros and Sisi providing a lot of pace,” he explained.
“Their midfield will be packed out with players to win the ball back and come out of defence quickly.