Eden Hazard admits he and Chelsea have not been "up to scratch".
Manager Jose Mourinho singled out Hazard following defeat by Crystal Palace.
"It's obvious," he told L'Equipe. "You don't need to know too much about football to compare what I did last season and what I did this season. I'm not as good.
"It's more of a collective problem than an individual one. We're professionals. We knew this season was going to be more difficult... but within the squad we have the quality to bounce back.
"Individually and collectively, we're not up to scratch,' he added. 'Starting with me."