Atletico had gone four home matches in all competitions without a win prior to Tuesday's 1-0 victory over German visitors Leverkusen in Madrid.
Simeone's side had also only scored once in their previous three fixtures at Wanda Metropolitano, where Alvaro Morata's 78th-minute header settled the Group D contest.
"I feel good when I see passion and the team had it," head coach Simeone told reporters when asked about his mood after Atletico joined Juventus on seven points atop the group.
"The team knew what they were playing at. We could play badly or well, but they knew what to play at. There was a way and when we're on it, we're closer to things coming out."
"We try to face each game as if it were the last, either Copa del Rey, LaLiga or Champions League," Simeone, whose Atletico are fifth and three points adrift of LaLiga leaders Barcelona, said. "We don't stop to think about what might happen four games ahead.
"We focus game by game, that's the way we look into this matter. We knew today [Tuesday] was an important game, against a rival, that plays very well. Certainly, you had to make a very high concentration effort."
Atletico star Koke – who emerged from the club's youth system in 2009 – was the target of boos in the Spanish capital and Simeone added: "I think people always do what they feel and what they see at that moment. Because this is football.
"I remember the time of Luis Aragones, Caminero, Kiko ... They have booed us all. So in football, when there is moment you're not so good, people want you to play well today, but I am sure every Atletico de Madrid fan will express gratitude for Koke and thank him for what he has done and will do for the club.
"At the moment, like the manager, when we make a mistake. People are spontaneous, and in this moment they react to what they believe. We are the ones who have to look for those boos to become applauses."