The decision to rule out Alvarez's penalty was questioned by Atletico after the game. Alvarez appeared to slip while taking the kick and manager Diego Simeone felt it was impossible to tell whether he had touched the ball twice: "I've just seen the images, the referee says Julián touches the ball with his supporting leg, but the ball doesn't move. That's debatable, whether it was a goal or not. But I'm proud of my players, I'm honestly happy, because we competed in an exemplary way."
Any extra contact from Alvarez was minimal at best and it's difficult to see what, if any, advantage the Argentine gained. However, Atletico's decision to contact UEFA over the incident may now bring about a change to the rules.