Former Arsenal central defender turned pundit Martin Keown has hit out at Chelsea's back line, accusing them of ball-watching and not working hard enough.
The Blues have struggled at the back this season, with five of their nine goals conceded coming as a result of individual player error.
This has led to some lacklustre results in the Premier League so far this season, including two 3-3 draws at the hands of West Bromwich Albion and Southampton.
Although Frank Lampard showed no hesitation in splashing the cash to strengthen his attack over the summer with the additions of Kai Havertz, Timo Werner and Hakim Ziyech, Keown believes that Chelsea's defence is the area in desperate need of improvement.
"What has stood out is the mannequin-like ball-watching from Chelsea's defenders," he wrote in his column for MailOnline.
"They stand around admiring the pretty football being played in front of them rather than preparing for when they lose possession.
"They've had the cigars out, and that mentality has to change. Lampard's message to his defenders has to be: 'Get into position early and expect the forward players to lose possession at any moment.'"
The former England international, who was a member of Arsenal's 'Invincibles', stressed that the Blues need to cut naivety out of their game and focus on making the right decisions at the back.
He drew from his own experiences learning the game as a young player, recalling advice he received from influential coach Don Howe.
"As a defender, you have to be on red alert at all times. At Arsenal, I was lucky enough to work under Don Howe. I couldn't have asked for a better apprenticeship.
"Don was the governor of defending and we were taught: 'If you work early, you work less.'
"Where's the ball? Where's my opponent? Where's our defensive line? You have to assess, shuffle across, drop off – and it is imperative you do this before your team loses the ball.
"If you don't bother getting into position, then the opposition can and will hurt you at this level.
"That's what Chelsea's defenders need to learn. It is about knowledge, awareness and not being naive."
Chelsea travel to Manchester United on Saturday as they look to record an impressive victory and fire themselves back into the Premier League's top four.
