Diego Simeone acknowledged the feelings of frustration and "injustice" after Atletico Madrid's painful Champions League loss, but urged them to move on.

Atletico had scored a first-minute goal to level the aggregate score against Real Madrid in the second leg of their last-16 tie, with a penalty shoot-out needed to separate the teams.

VAR ruled Julian Alvarez's slip caused a double touch to rule out one of Atletico's penalties, with Carlo Ancelotti's side ultimately prevailing to reach the next round. 

Atletico now face another big match as they host Barcelona in LaLiga, with both sides fighting for the title in a tightly contested race for top spot.

"The only power I have is to work and ensure the team keeps competing," Simeone told reporters on Saturday. 

"I understand our fans and the feeling everyone has is frustration, anger and injustice."

Simeone was furious with the referee's decision to disallow Alvarez's penalty as Madrid won the shootout 4-2, with Antonio Rudiger scoring the winner after Marcos Llorente had struck the woodwork.

"I'm not going to comment further on the previous match. We have to focus on the upcoming clash," Simeone added.

"We have a great opportunity against a team that plays very well. We’re focused on ourselves and on showing the fans that we can keep competing."

The match against Barcelona could be a defining moment in Simeone's season. Barcelona are second in the standings with 57 points, one ahead of Atletico, who have played a game more.

Atletico won the reverse fixture in LaLiga against Barcelona ​​2-1, having lost their previous five against them beforehand; they have not completed a league double over them since 2005-06.

Simeone's side have confidence on home soil though as they have not lost any of their 14 LaLiga home games this term (W10 D4). Barcelona, though, are on a six-game winning streak in the top-flight, and would move back to the top of the table with a win on Sunday.

"It’s always important to maintain the right distance in the standings as the season progresses. For our chances, this match is about winning and closing the gap. If they win, they move closer to the title," Simeone said.

"Everything about them [Barcelona] concerns us. They are a very complete team, a brilliant side, and they’ve managed this past week well."