Mauricio Pochettino has described the decision to close the domestic summer transfer window in early August as a “massive mistake” and claims he has even persuaded Tottenham’s hard-nosed chairman, Daniel Levy, of the same thing. Pochettino could still lose Christian Eriksen to Real Madrid as the Spanish transfer window does not shut until 2 September. Were that to happen Pochettino would be unable to replace one of Tottenham’s key players until January at the earliest. Italy, France and Germany have the same deadline as Spain. “I wasn’t in agreement [with the decision] but at that moment they believed that was best for the clubs,” said the Spurs manager. “But I think he [Levy] and a lot of people now realise it was a massive mistake. I hope that we fix the problem for the next season. “We need to go back and operate in the same way that they operate in Europe because I think it’s massive when you go to compete in the Europa League or Champions League. Champions League teams can create a problem for a team like us and it’s so clear that I cannot be happy as a coach that in the last three weeks clubs…