Pep Guardiola believes Real Madrid deserve to be top of La Liga because they have been better than Barcelona so far this season. Los Merengues lead Barça by three points heading into this weekend\'s round of matches, and the latter\'s coach has admitted that it has been getting harder to win the title each campaign. \"The reality is that we are for the moment behind a team that has been better than us this season,\" said Guardiola, who last term guided Barcelona to their third successive league crown and a UEFA Champions League semi-final elimination of Real. \"The competition is once again really going to test us. Each year it becomes more and more difficult to win, and this year will be no exception.\" Barcelona may well be six points adrift going into Sunday\'s derby with Espanyol - Real host struggling Granada tonight - but Guardiola is not expecting an easy ride from their opponents. \"Espanyol are not only a young team who battle and pressurise other sides, but also a team that have a good tactical sense,\" said the former Spain midfielder. Guardiola also ruled out adding to his squad during the ongoing transfer window, despite having lost forward David Villa to a long-term injury. \"We will not be involved in the transfer window,\" he declared. \"We are what we are, and we will play according to that.\"