Atletico Madrid are good in starting well, but once the season get to the middle then you will begin to see them reducing points that will make them not to recover till the end of the tournament.
Atletico is indeed a great club. However, they have gaps in terms of squad depth. Substitute players do not have the capacity and capability to approach the main players. It was not visible at the start of the season. But in the middle of the season, a busy match schedule and the risk of injury are a scary threat for teams that don't have good squad depth.