Atletico was the only team to beat Madrid last season. While the win over their rivals in the league did little to disrupt Real's dominant run, the Copa del Rey victory ended Real's hopes of a historic treble.
"A lot has changed up to this moment. It's an aspect in which we’ve improved, and that’s why the club has grown as it has, and the team is held to the standards it is," Simeone told reporters on Saturday.
"Everything starts in the mind. Beyond the physical aspect, which can have an influence at times, motivation is an important weapon for everything in life."
Real Madrid players head into the derby with an advantage, having rested an extra two days. Atleti played their midweek match on Thursday at Celta Vigo, while Ancelotti's men hosted Deportivo Alaves on Tuesday.
The Argentine coach said it was hard to manage with the lack of preparation time, having said earlier that he is working on easing player workloads during training.
"It’s tough to change things in two days, based on what we’ve been doing," Simeone said. "We are still in the process of finding our balance, we are adapting and we get it right more or less. But it is true that we need more time.
"We accept it as it is. We said it before when we went to play against Athletic Bilbao in the (Copa del Rey) semi-final, them with five days and us with two days of rest. No one cares."
Atleti’s only home defeat this year came in February's Copa del Rey semi-final against Bilbao, who went on to win that title.
Simeone said Madrid boss Carlo Ancelotti has plenty of firepower despite missing Kylian Mbappe to injury, pointing to the likes of playmaker Jude Bellingham. But he added that Real would miss the influence of Toni Kroos, who retired last season.
"The opponent has lost a very important player like Kroos. I think they are looking for that player who gives them that calm to take advantage of all their offensive power," he added.
