Both teams had a player sent off as Atletico won the Champions League tie 2-1 thanks to Alvarez's brace.
He said afterwards: "I'm very happy with the three points. It wasn't easy. Because of everything that happened in the game, being one man down, they scored a goal against us, things looked a bit bleak, but by playing our game, with humility we got the equaliser and then 10 against 10 we saw the chance to win.
"These are three very important points and serve to keep us believing in what we do.
"It was a great night, we are very happy, we won a match that was difficult in the first half with one less player, but Cholo asked us to stay calm and stay together, the situations were going to come and they did.
"It is a sign of work and sacrifice, we have shown it in other matches by fighting until the end."
Of his own form, Alvarez added: "There are always good streaks and others that are not so good, but I feel very good, the team is helping me a lot to show what I have and continue growing as a player and as a person."