Los Rojiblancos are set to face Los Pepineros at Estadio Municipal de Butarque in a matchday two fixture, their eyes firmly set on registering their second win of the season.
"We all know how difficult it is to play against Leganes away from home," Partey said in a video interview with his club released on social media.
"We know that it will be a complicated game.
"We have to do everything well in order to play a good game and win."
The midfielder also spoke on the club's summer signings, who are expected to bring back belief to Wanda Metropolitano following the departure of star man Antoine Griezmann.
"The new players are really exciting the fans," Partey explained.
"I hope the fans give these players confidence. I hope they support them and help the team.
"They [new players] already know almost everything of the club's identity.
"There is a lot of talent there, which has been added to the team.
"I hope everything goes well and that they can contribute a lot."
Last season, Partey made 32 La Liga appearances for Atletico, starting 22 of the games and scoring three times.