A comeback draw away to Real Betis, a shock home defeat to city rivals Espanyol, and another comeback draw away to Olympique Lyon in the Champions League have shattered the illusion of Barca's invincibility.
Their lead at the top has been cut from 12 points down to seven with chasing Real Madrid on a nine-match winning streak, and the belief is growing in the capital that they can overhaul their arch-rivals to snatch the title as they did in 2007.
Pep Guardiola's team have already beaten Atletico three times this season, giving them a 6-1 league drubbing at the Nou Camp, and winning both legs of a King's Cup last 16 tie.
"Taking Aguero off was not a good decision because he was playing a good game. He is a reference for us within the team and he should always be there," Atletico midfielder Maniche told radio station Onda Cero afterwards.
"It was a turning point for us. We gave one of the best teams in Europe a lot of problems and now we need to do the same against Madrid. It is the way forward," said striker Luis Garcia.
Third-placed Sevilla visit their King's Cup semi-final opponents Athletic Bilbao on Saturday. The Andalucians have a 2-1 first leg lead from last month, and can test the atmosphere at San Mames ahead of next week's second leg.
