Real Madrid coach Jose Mourinho has accepted responsibility for his side\'s awful start to their 2012/13 La Liga season which has already seen them fall eight points behind rivals FC Barcelona after just four games. The Spanish champions get their UEFA Champions League campaign under way against Manchester City this evening, and after criticising some of his players\' concentration levels after 1-0 defeat to Sevilla on Saturday, Mourinho believes his squad must put their success from last year behind them and concentrate on the season ahead. He said: \"I don\'t believe I have created doubts. The principal person responsible is me. When my teams win, we win together, and when we lose, I am the one responsible. \"Before losing to Sevilla I said to the players what I then said in the press conference. For this reason it is not a criticism but a conviction. I said it to them before the game. \"Football is about today and tomorrow, not yesterday. Yesterday is history. I haven\'t been able to keep my players motivated and concentrated at the top level and that is my fault.\" Midfielder Sami Khedira believes that the players also have to accept their share of the blame but is looking forward to putting recent disappointments behind them against City. \"The boss has a responsibility, but we also have the responsibility to play well. We have to do better in order to get the best from ourselves. \"What the manager says is right. We played badly in Sevilla. He has the right to speak as he wants about us in public, but (the City game) is a good occasion to rediscover our form and to give 100%. \"The group has four teams of the highest level. I am always happy to play against the best and in the group stages even more so. I think all of the games will be decided by small margins because we are on a very equal level.\" FIFA