Even if we lose this and that's a big "if" considering how Atletico been doing this season, it will not be the end of the world. We can still beat them at home and have better results against the remaining teams in the group. I think in recent years it has been proven that group stage does not mean much. For example, last season finalists, LFC and Spurs, had the same amounts of points as the 3rd team in their groups.