Filipe Luis is frustrated Diego Costa will be unable to face his former club Chelsea when Atletico Madrid look to salvage their Champions League campaign at Stamford Bridge on Tuesday night.
Atletico need to beat the Blues away from home and hope that Qarabag at least avoid defeat at Roma if they are to progress to the knockout stage of the competition.
Costa forced through a return to Atletico in September after falling out of favour at Chelsea but the striker is ineligible to play for Diego Simeone's side until January due to the club's ongoing transfer embargo.
Luis, who himself rejoined Atletico from Chelsea in 2015, admits he is frustrated by Costa's absence.
"Diego is a huge player. He scores a lot of goals and important goals," Luis said. "It is frustrating seeing him playing like an animal, but he can't play. It's just a month until he can play with us. He'll help us a lot.
"He came back to Atletico because Chelsea couldn't keep him because it's his desire. He really wanted to come back to Atletico.
"He knows the club, he knows the way we play. He has already adapted.
"I know it was difficult times for him and for Chelsea. Now everybody's happy. We want to see him play and happy again."
Atletico failed to win any of their opening four games in Group C and remain two points behind second-placed Roma, despite beating them 2-0 at Wanda Metropolitano last time out.
Both Simeone and Luis insist Atletico's sole focus will be on beating group leaders Chelsea on Tuesday, and not on Qarabag's crucial trip to the Stadio Olimpico.
"We don't have to be looking about what happens in Rome," Simeone said.
"We just have to think about us. It's not going to be a simple game. We need to take the game to where we feel we can hurt them.
"It's a personal challenge to fight for everything we've worked for these last few years and keep our values there."
Luis added: "It depends all on us. We need to win and then we'll have to wait. We can't do anything else.
"If we don't manage to qualify, we will have to concentrate on what comes, on the next competition, and try to win those games."