Atletico will face Marseille in the Europa League final on Wednesday night.
Diego Simeone surprisingly named a full-strength starting line-up for the game, despite having the Europa League final just four days away, but Atleti made the most of some early dominance through a fine Koke finish.
Atletico Madrid all but secured second place in LaLiga with a 1-0 win over Getafe in a combative clash at Coliseum Alfonso Perez.
Manager Zinedine Zidane left Ronaldo off his squad as Madrid's star recovers from a right ankle injury that caused him to be substituted last weekend at Liga champion Barcelona. Francisco "Isco" Alarcon, little-used defender Achraf Hakimi, and Toni Kroos added on, along with an own goal by Celta's Sergi Gomez, to ease to the big win at home.
The capital club got off to a quick start in the local derby, as Koke collected Antoine Griezmann's pass and drove a low shot into the bottom corner to score his fourth goal of the campaign in the eighth minute.
Atletico goalkeeper Jan Oblak also saved a late penalty from Faycal Fajr as Diego Simeone's men warmed up for Wednesday's Europa League final against Marseille by denting Getafe's hopes of playing continental football next season.
Atletico have had the pain of losing two Champions League finals to neighbors Real Madrid in 2014 and 2016 and this is another chance for European glory for the club. Atletico maintained its hold on second place in the league.
Villarreal are fifth on 60, Betis sixth on 60 and Sevilla seventh on 55, three above Getafe and with a better head-to-head record than the Madrid side.