Chelsea manager Mauricio Pochettino said his players have to avoid getting into a comfort zone during games and that they must demand more of themselves if they are to pick up wins in the Premier League.
Chelsea, who host Manchester United later on Thursday, spent more than 400 million pounds ($510 million) to bring in 13 new players last year.
Despite the outlay, the young squad have struggled for consistency and after being held 2-2 by relegation-threatened Burnley on Saturday the club are in 12th place.
Asked if he fears his squad's mentality is hindering them from competing at their full potential, Pochettino agreed.
"Never be in a comfort zone. If you are in a comfort zone you drop your level, you drop your standards," he added.
"An example is the last game. That is why we are in the process to build something. That is why we are not winning in the way we expect.
"It is because we still need to create a mentality that is going to help us. You need to demand more from yourself and teammates. Potential (is present) but we need to win today."