Barcelona twice led against Atletico on Saturday but it ended 2-2. on Tuesday night against Atlético Madrid at Camp Nou.
An own goal and a 700th career goal for Leo Messi made it 1-0 and 2-1 to the defending champions, but two Saúl penalties meant two costly points have gone begging in a tense, gripping encounter.
Barcelona are now 1 points behind league leaders Real Madrid.
Real Madrid welcomes Getefe at Santiago Bernabeu on Wednesday and would need a win to extend their lead in the competition.