La Real finished fourth in La Liga last season, but have won just one of their opening eight fixtures in the new campaign, with a total of seven points leaving them in 15th position.
"I think what is happening is that it is the small details that have made the difference," he told Mundo Deportivo.
"There have been games where we have been good in the first half and improved in the second, but the ball has just not gone in. In other matches it has been a little thing that has changed everything. At the moment luck is not favouring us but we mustn't think like that.
"I think that we need to believe, carry on the same, and work as we have been doing so we have a clear conscience. Things can go well, badly or just normally but what you can't afford to do is lower the work rate."
Sociedad have also lost both of their Champions League Group A fixtures - to Shakhtar Donetsk and Bayer Leverkusen.