Saul Niguez struck the game's only goal after Angel Correa was brought down for a penalty.
"It is not easy to always win and we are competing well with fantastic players who play in various positions during a match," Simeone said after the game.
"It is our strength, that is where we feel strong.
"The introduction of Saul, Lemar and Correa up top gave us vital speed."
"We are doing what we can, intending to hold down our place in the leage and to improve each match to remain motivated."