I was really shocked after the result. Atletico Madrid managed to beat Barcelona away in the La Liga after 18 years...

It isn't a win at Camp Nou though but anyways.
I think the turning point of the game was Raphinha's lob shot hitting the upper post. If he scored there, Barcelona were going to make it 2-0. I think Atletico Madrid wouldn't manage to come back from that.
After that Simeone did his magic somehow again. A last minute winner brought the 2-1 win to his team.

I don't remember exactly but it must be like their 13th or 14th goal that came in the stoppage time this season. They are really in this title competition.
The result of the match of Barcelona against Atletico Madrid will be a surprise to some people but for me I expect Barcelona to lose or end the game draw, I have been saying that Barcelona will find it difficult to defeat Atletico Madrid because Atletico Madrid is in good shape this season, Atletico Madrid have played about 12 games now and they never lose any match which shows that they can play well against any opponent, Barcelona played well in the match but Atletico Madrid score goal to get the 3 points.
Barcelona dominated the game from the beginning of the match and even in the second half Barcelona still dominated game but what Barcelona lacked in the game was to convert the chances they had to score a goal, Barcelona players missed a lot of chances and if you look at any game that Barcelona is missing chances they always find it difficult to win the match, Barcelona might end up being at the third position in the League table if Real Madrid win their game.