Madrid or Barcelona have yet to face a truly strong team in La Liga. it's still early days and consistency to keep winning is very rarely seen in the league competition. especially with La Liga where there are strong teams competing with each other.
Madrid and Barcelona have great opportunities for this season. Madrid must immediately maintain a distance of points at least in the first 10 matches if they want to be safe enough from Barcelona's pursuit. Madrid, with the quality of their players evenly distributed, should have a greater chance of maintaining the consistency of their performance than Barcelona.
In next five or six weeks things are looking not tough for these top teams because most of the opponents are having not enough quality to handle them with both are giving their best which is also not comparable in La Liga where difference of quality is having big difference but still injuries and sometime extraordinary performance can give them shocking results.
Right now I have feeling there is no match which is going to have serious impact on these two top teams, and they are going to have any trouble Real Madrid is going to host Real Sociedad in fifth round and then having derby against Atlético Madrid in sixth round and Barcelona which is currently trying to adopt better strategy also having 3rd round match against Villarreal at Estadio de la Ceramica which is surely not easy game but still manageable for the Barcelona.