Barcelona and Real Madrid maintained their 100% starts to the season with La Liga victories on Sunday.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.