Eden Hazard insists Chelsea can make no excuses for their shock 3-0 loss to London rivals Arsenal.
The Blues had been undefeated in their first four Premier League games under Antonio Conte, but were beaten 2-1 at home by Liverpool before following that up with an embarrassing reverse at the Emirates Stadium.
Arsenal scored three times in the opening 40 minutes, leaving Chelsea with no way back, and Hazard acknowledges his side must improve.
"There are no excuses," he told the club's official website. "It was not good. We lost too many duels.
"We came to win the match but we made mistakes - for the first goal, another for the second and then before we knew it we were already 3-0 down.
"Every weekend at the moment we having to come back and score. We did it at Leicester but against Arsenal, who were playing at home, it was not possible.
"They played well. We need to be better. In the last three games in the league there have been nine points available and we have got one. It is disappointing.
"We need to go away and work on what we are doing wrong ahead of the big matches that are coming up."
With no European football this season, Chelsea's next test comes away to Hull City on Saturday.