Jose Mourinho's side was unconvincing before halftime but Samuel Eto'o sparked a stunning revival by taking advantage of Jan Vertonghen's slip and ill-judged back pass to nip in and score in the 56th minute.
Eto'o was then felled by Younes Kaboul in the area, earning the defender a straight red card, and Eden Hazard converted the 60th-minute penalty. Substitute Demba Ba completed a crushing win with two late goals in the space of 75 seconds.
Chelsea has played a game more than second-placed Liverpool and third-placed Arsenal, who are both seven points adrift and not in league action this weekend. Fourth-placed Manchester City is nine points behind with three games in hand.
This was meant to be one of Chelsea's toughest matches of its run-in and a win _ coming despite a poor first half _ can only strengthen belief inside Stamford Bridge that the title could be theirs in Mourinho's first season back in charge. Chelsea has Arsenal at home and Liverpool away in its final nine matches; otherwise the schedule looks straightforward.
And although City is in striking distance, points on the board are what matter at this stage. Chelsea has had the knack this campaign of winning without necessarily playing well and this was another case in point, taking its unbeaten run in the league to 14 games in the process.
Spurs had drawn or lost on their previous 26 visits to Stamford Bridge, dating back to February 1990 when Gary Lineker scored the winning goal, but they looked in good shape to end that dreadful record in a first half that they edged.
Hazard may have missed an open goal in the fifth minute after rounding goalkeeper Hugo Lloris, but most of the action was at the other end where Nabil Bentaleb dragged a shot wide, Sandro had a superb volley saved and Tottenham's fluid midfield caused all sorts of problems.
But the visitors failed to make their dominance count and the inevitable happened at the start of the second half _ Chelsea took full advantage.
The first goal can be put down to Vertonghen's unfortunate slip, although the Belgium defender compounded his error by trying to hook the ball back to Lloris while scrambling on the ground. Eto'o intervened and slotted a low finish into the corner.
Eto'o, who was only playing because Fernando Torres was injured in the warmup, was then bundled into by Kaboul from behind as he latched onto Hazard's square ball. Kaboul was shown a straight red card and Hazard rolled home the penalty.
From then on, it was damage limitation for Spurs and they resisted until the final two minutes.
Ba tucked home a finish after Sandro made a mess of clearing Oscar's cross and then Kyle Walker's strange headed backpass was pounced on by Ba, who finished under Lloris.