Indeed whilst the 'new' Mourinho may not be as explosive as he once was, neither are his new look Chelsea squad. They have looked very much lethargic in their build-up play; a deficiency that far belies the incredible offensive threat they have, the worst performer being Samuel Eto'o.
Considering how miserly Tottenham's defence has been this season (8 clean sheets in 9 games), a no show from any of Chelsea's strikers cannot be tolerated. It is for this reason Juan Mata has to play, whatever tactical gain Chelsea reap by not playing him, they lose severely in attacking impetus. He would be able to hold up the ball longer and bring others into play. Should he not play, expect a ravenous Tottenham defence to snuff out any chances they fashion.
For this reason and also for the fact Tottenham have home advantage, they will hope Ramires plays today (currently a doubt). If as I expect Tottenham hoard possession, they will need Ramires to play. His ability to win the ball back is only matched by Mikel in the midfield, considering he is far more mobile than Mikel it is an even more impressive feat that he has managed to achieve the statistics he has (15 in 5 matches or 3 on average).
Tottenham 1-1 Chelsea
*All statistics courtesy of WhoScored