Thibaut Courtois claims Chelsea's club-record winning streak was kick-started by back-to-back Premier League losses in September.
Antonio Conte's side beat Bournemouth 3-0 on Monday to make it 12 top-flight wins in a row, a run that started following consecutive league defeats to Liverpool and Arsenal.
And goalkeeper Courtois concedes those two results were a wake-up call for the Blues, who put up a meek defence of their title last season, finishing 31 points behind champions Leicester City.
"We knew that maybe our mentality was not right in those two games we lost against Liverpool and Arsenal," said the Belgian in quotes reported by The Daily Star.
"They were tough games and we didn't have the same intensity as Arsenal or Liverpool. If you don't put the same intensity in as the other side, you will not win that kind of game.
"So that's why we talked as a team about making a step up at that point, because we didn't want to have the same season as last year. We needed to step up and that's what we did.
"Obviously with the current run of wins of course we would say we are doing maybe better than expected after a bad season last year.
"We are top of the league with more points than we had after this many games when we were champions two years ago.
"So that says we are doing well, but we have to keep on working hard and fighting a lot against the teams who defend more and are hard to break down.
"We will try to do our best and keep the run going."
Next up for Conte's side is the visit of Stoke City on New Year's Eve.