Predictions have shown that Frank Lampard's side are still at risk of finishing in the relegation spots this season.
Currently sitting on 39 points with six games left to play, 11th-placed Chelsea have not yet secured mathematical safety in the Premier League.
An own goal from veteran defender Cesar Azpilicueta and a 78th minute strike from Bryan Mbeumo secured a historic derby win for Thomas Frank's Brentford on Wednesday night.
The 2-0 home defeat to Brentford was Chelsea's fifth straight loss under Lampard, who was ushered in as caretaker manager earlier this month following the sacking of ex-Brighton flop Graham Potter.