The 23-year-old, who moved to Betis on a season-long loan in June, is preparing to face Atletico for the first time in the La Liga clash at Estadio Benito Villamarin on Wednesday.
In-form striker Radamel Falcao looks set to lead the visitors' line, with Atletico travelling to Betis so far unbeaten in La Liga with three wins and a draw to their name.
"It's a different game, the first time I will play against them, so it is nice for me," Perez told www.realbetisbalompie.es.
"But it is also of great importance. I don't feel pressured to play against them."
Perez knows Falcao will pose a huge threat in attack.
"He is the striker who is fittest," Perez said. "We will look at it and we will decide what the best way is to defend against him."
Betis have won their last two games against Espanyol and Valladolid and go into the game one point behind Atletico in the league standings.
Atletico manager Diego Simeone is hoping to continue his team's good run in Wednesday's game.
Atletico have won their last three games following an opening day draw against Levante.
Asked about the importance of getting as many points as possible, Simeone said: "On Wednesday we have a difficult game against a team that plays well. We will not stop to look at the numbers."