Athletico Madrid 4 - 3 Barcelona
Barcelona coach Pep Guardiola has told the club's players and supporters not to panic after successive defeats cut their lead over Real Madrid to only four points.
Earlier in February La Liga leaders Barca were 12 points clear of Madrid.
But since their 2-0 Clasico defeat in Juande Ramos's first match in charge, Los Merengues have won 10 Liga matches on the trot, while Los Cules slumped to defeats at home to local rivals Espanyol and - despite leading 2-0 and 3-2 during the match - at Atletico Madrid.
"We have had a big advantage and Real Madrid have cut it back by eight points in three weeks. But we will continue forward," said Guardiola. "We lost a game which was up and down, very exciting and I have to give credit to Atletico but we will now continue as before.
"Atletico play a very direct style of football and it caused problems. It was a game with plenty of chances, typical of an Atletico Madrid versus Barcelona game."
Atletico coach Abel Resino, whose team occupy fifth place, singled out his players' battling qualities.
"Against a good side we had a first half where we maintained our composure despite the onslaught. Each day I feel as though we are getting better and the team has shown character," he said.
"We never eased off despite being 2-0 down. Sergio Aguero was sensational and his attitude has been contagious."