The Blues were crowned champions during the 2016-17 campaign but could only finish fifth last season, a full 30 points behind eventual winners Manchester City.
That led to Antonio Conte being replaced as manager by Maurizio Sarri but the pressure is already on the Italian, with Chelsea sitting sixth in the standings heading into a busy midweek of action.
Chelsea – priced at 2.20 to claim a top-four finish – will host third-placed Tottenham on Wednesday in a match that could define not only their season but also Sarri’s long-term future.
The Blues have lost heavily to both Bournemouth and Manchester City over recent weeks while they have also been knocked out of both domestic cup competitions.
Brazilian defender Luiz feels going from being a title challenger to fighting for a top-four finish has been difficult for the Chelsea players.
“Chelsea is a team which should be fighting for the Premier League and now we are seeing it is a bit far, so it is not the same mentality. It is up to us to pass this step,” Luiz said.
Tottenham were the first side to beat Chelsea in a competitive match under Sarri, claiming a 3-1 victory at Wembley back in November, although the Blues did secure their revenge by beating Spurs in last month’s Carabao Cup semi-finals via a penalty shootout.