Chelsea have conceded nine goals in their past four matches, having been beaten by Arsenal and Liverpool, drawn with Swansea and come from 2-0 down to beat Leicester.
The Blues failed to sign Antonio Conte’s primary defensive targets over the summer, but the Italian will reportedly conduct an overhaul of his backline in January.
And Hazard admits Chelsea have been their own worst enemies.
“We came to win the match but we made mistakes,” he said of the defeat to Arsenal.
“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 are having to come back and score. We did it at Leicester but against Arsenal, who were playing at home, it was not possible.
“We need to go away and work on what we are doing wrong ahead of the big matches that are coming up.”