Is that the fault of Mourinho, Fabregas or simply down to Guus Hiddink? It's something we may never know...
But what Chelsea fans do know is they're seeing what the Spaniard can really do again. Against former club Arsenal, the 28-year-old was deservedly handed the man-of-the-match award.
And Chelsea fans duly took the opportunity to rave about Cesc... and mock Mesut Ozil!
Indeed, the Arsenal playmaker wasn't able to register an assist on Sunday afternoon - a rarity that could have been avoided had the Gunners remained 11 men strong all game long.
Fabregas, by contrast, dictated play as Chelsea did what they do best and frustrated Arsenal.
Here's what supporters in west London were saying about Fabregas and Ozil on Twitter. One definitely enjoyed a better day than the other on this occasion...
Has gotten a lot of harsh flak recently but Fabregas was excellent today. #CFC— Peter McNamara (@PeterMcNamara_) January 24, 2016
Cesc Fabregas is the Barclays Man Of The Match! #CFC— ^^SUPER FRANK^^ (@Up_The_Chels) January 24, 2016
We all expected to see magical Ozil but Cesc Fabregas stole the show What a midfield performance from him!!! #CFC Same old Arsenal— Obinna (@iam_OBINO) January 24, 2016
What a victory and Fabregas man of the match too make it even better! #cfc— Al G (@alexgoddard8) January 24, 2016