Eden Hazard gave them the lead following a swift 25th-minute counter-attack earlier than Diego Costa bundled the ball residence shortly after the break to place the Blues in management at London Stadium.
West Ham's Manuel Lanzini grabbed a comfort in added time, however the end result was by no means unsure.
Mid-table West Ham, who knocked Chelsea out of the League Cup this season when crowd hassle marred the night time, provided little menace for a lot of the recreation because the west London aspect continued their surge in the direction of the title.
Antonio Conte's staff, who've gained 21 of their 27 league matches this season, have 66 factors, 10 forward of second-placed Tottenham Hotspur. Manchester Metropolis can scale back the hole to eight in the event that they beat Stoke Metropolis on Wednesday.
"I feel we performed a superb recreation. We managed the sport. It is a pity for the objective we conceded on the finish," Conte, who saluted Chelsea's followers on the finish, stated."However I am happy. We confirmed nice focus and dedication and can to win."
Chelsea have been content material to take a seat deep and draw West Ham's sting for the opening 20 minutes by which the house aspect loved loads of the ball with out troubling goalkeeper Thibaut Courtois.
Striker Andy Carroll obtained a bloody nostril for his efforts as he made his presence felt within the field beneath a collection of excessive crosses however Chelsea have been unruffled.
When the chance introduced itself, although, Chelsea have been primed and launched a deadly counter-attack to take the lead.
Midfielder N'Golo Kante intercepted a stray Robert Snodgrass move deep inside his personal half and instantly launched Hazard who exchanged passes with Pedro earlier than rounding keeper Darren Randolph to fit residence his 11th league aim of the season.
Chelsea took management after that and may need secured the factors earlier than halftime had they been a bit of extra medical.
One other breakaway ended with Victor Moses, who was on mortgage at West Ham final season when the Hammers completed 12 factors above Chelsea, having a shot blocked by Aaron Cresswell earlier than Randolph saved nicely from Pedro's close-range follow-up effort.
Lanzini wasted West Ham's greatest probability when he fired properly over the bar from a central place.
Chelsea then went additional forward 5 minutes into the second half when Hazard's nook skimmed off the top of West Ham's Pedro Obiang and straight to Costa who couldn't miss.
West Ham roused themselves and Sofiane Feghouli had a shot cleared off the road earlier than, seconds later, residence defender Jose Fonte headed over with the objective at his mercy.
Costa appeared sure to double his tally with an excellent flip after an equally spectacular move by the electrical Hazard however his shot was clawed away by Randolph.
The closing levels have been performed out earlier than many empty seats as West Ham's followers drifted house whereas Chelsea's sang "We will win the league".
It was onerous to disagree, though Lanzini did present one thing for the hosts to cheer with a stoppage-time strike.