The Frenchman insists his team simply had an off day.
"When you lose a game the solution is not always to buy," he told the club's official website. "Did we play at our best? I say 'no' and so we have to look at why.
"We had problems to win our first few games last year but we won them. This year we did not win – that is the reality. We had 60 minutes to come back on Fulham and we did not do it.
"Is that down to Fulham's quality or the fact we were not good enough? Only the future will tell us that."