Maurizio Sarri’s side were swept aside by the reigning Premier League champions at the Etihad Stadium on Sunday in their heaviest defeat since losing 7-0 to Nottingham Forest in April 1991.
The Blues shipped four goals within the opening 25 minutes on a torturous night for their fans and Azpilicueta, who conceded a penalty in the second half to gift City their fifth goal, admitted there was a lack of togetherness in his side’s performance.
“It’s difficult to find the words to describe my feeling after the game,’ the defender told Chelsea’s official website.
“It is one of the worst nights in my career. It’s very frustrating, it’s very disappointing. We have lost big games in the first minutes and we are conceding a lot of goals. We cannot accept that.
“When you lose 6-0 everyone has to accept they didn’t play well, we made errors that in big games like this you cannot make. We knew we had one of the best teams in front of us, and we knew it would be tough.
“When we won against them at Stamford Bridge it was because we played a very good game all together. This time It was not the case.
“To lose in this way is very disappointing. The only thing I can say to the fans is sorry, because it’s not acceptable, and I feel sorry for all of them.”
The defeat left Chelsea in sixth place in the Premier League table, but just one point off Manchester United in the fourth and final Champions League spot.
