Under-pressure manager Maurizio Sarri made the bold decision to drop goalkeeper Kepa Arrizabalaga in favour of Willy Caballero.
The Spaniard’s antics against Manchester City at Wembley on Sunday angered many at Stamford Bridge when he refused to be substituted.
But Chelsea showed they are still behind the Italian with a deserved victory over their London rivals thanks to Pedro’s opener midway through the second half and a comical Kieran Trippier own goal late on.
Chelsea remained in sixth spot, three points behind fourth-placed Arsenal having played a game less.
Third-placed Tottenham’s slim title hopes now look extinguished after a second successive league defeat and they could have few complaints after a disappointing derby display.
Gonzalo Higuain was denied by the post early on for Chelsea while Spurs midfielder Harry Winks rattled the crossbar just before halftime.
Pedro fired Chelsea in front in the 57th minute, turning inside Toby Alderweireld before beating Hugo Lloris from a tight angle.
Tottenham huffed and puffed but shot themselves in the foot in the 84th minute when Trippier and goalkeeper Hugo Lloris got in a tangle and the full back’s attempted back pass rolled in.
Tottenham are four points above Arsenal, who they host on Saturday, and five points above Manchester United. (Reuters/NAN)