Lionel Messi notched a hat-trick in Barca's 3-2 victory in Valencia , while Cristiano Ronaldo was on target as Real out-played Athletic Bilbao 3-1.
Messi fired the visitors into a three-goal lead before Helder Postiga hit back with a brace for Valencia in the space of 50 seconds.
All five goals came in an action-packed first half.
Meanwhile, Isco scored twice at the Bernabeu where Ibai poached a 79th minute consolation for Bilbao.
Both Spanish giants have taken nine points from their opening three games.