When we look at the situation, I think Atletico Madrid's chance of winning the championship has decreased. There is currently a four-point difference between them and the leader Barcelona and Barcelona has one less match. If Barcelona wins its missing match, the point difference will decrease by seven points. Therefore, Atletico Madrid will not have to lose any of its matches from now on. However, we see that they are losing points even in the matches they are the favorites.
In terms of percentage chances, Atletico Madrid does have a smaller percentage than the 2 teams above them. However, that does not mean they have completely lost that chance, because they still have several matches and the championship title has not been claimed. They can only continue to play and hope that the team above them has bad luck, so they can take advantage of the situation. On the other hand, it is also difficult to depend on fate on other teams, because they cannot do something that can make Real Madrid and Barcelona get negative results. Now they only need to focus on themselves.
Atletico is still in the race, and they still have a chance to control the competition that has formed around Barcelona and Real Madrid. With only focusing on La Liga and the Copa del Rey, Atletico workload to perform consistently until the end of the season should be a bit easier. Therefore, I think Atletico can still be considered a title contender at this time.
The majority of the teams Atletico will face in the future are mediocre clubs, currently outside the top ten in the standings, except for Real Betis and Rayo Vallecano. This can also underline that their chances of winning a trophy are still quite large, the momentum to close the 4-point gap is still wide open, as Barcelona and Real Madrid have to split their focus in the Champions League.