Barcelona were held to a 1-1 home draw by Atletico Madrid on Thursday, a result which leaves the champions three points behind league leaders Sevilla going into the two-week Christmas break.
Ronaldinho put Barca in front four minutes before halftime with a free kick, whipping the ball across the face of the wall and into the opposite corner from a metre outside the area.
Atletico's teenage striker Sergio Aguero equalised for the visitors when he clipped the ball past keeper Victor Valdes with the outside of his foot on the hour.
Sevilla top the table on 37 points from 16 games after their 4-0 drubbing of Deportivo Coruna on Wednesday, Barca follow on 34 but have a game in hand.
Real Madrid, who slumped to a 3-0 defeat at home to Recreativo Huelva on Wednesday, are a further two points back in third, four clear of Atletico.
Barca, still smarting from their 1-0 defeat to Internacional in the final of the Club World Cup last weekend, had the better of the opening exchanges as they deprived Atletico of possession and flicked the ball around the midfield.
Deco and Xavi both went close with long-range efforts, but the visitors managed to hold firm as looked to play on the counter-attack.
CONGESTED DEFENCE
Barca were finding it difficult to find a way through the congested Atletico defence, but they were given a break just before halftime when they were awarded a free kick on the edge of the penalty area.
Atletico keeper Leo Franco agonised over the organisation of his defensive wall, but Ronaldinho outwitted the Argentine with a sublime strike over his team mate Juliano Belletti and into the corner.
The expertly taken free kick took the forward's tally to 12 goal's this season, two behind leading scorer Frederic Kanoute of Sevilla.
Atletico lived up to their reputation as Barca's bogey team, however, when they hit back 15 minutes into the second half.
Aguero outpaced Barca central defenders Lilian Thuram and Carles Puyol to latch on to a fine through ball from Peter Luccin before clipping his shot into the corner of the net with the outside of his foot.
Barca, who had lost three of their previous four games against Atletico, pressed hard for the final half hour but were unable to break down the rugged opposition defence.
