In theory, there is still time for Chelsea's rivals to catch and overhaul them at the top of the Premier League. In reality, though, it is beginning to feel almost inconceivable. Chelsea just look too strong, too experienced and too streetwise. They passed their latest test with distinction and it would have to be something dramatic now to imagine any other scenario than another open-top bus parade along the King's Road. Another team in Chelsea's position might have wobbled in the circumstances – a London derby under the floodlights against an improving side – bearing in mind their two nearest challengers, Tottenham Hotspur and Manchester City, both won over the weekend. Nobody, however, should doubt the durability of the side Antonio Conte has put together. Their lead is back to 10 points and who can foresee a collapse when Eden Hazard is shimmering with this kind of menace and everyone around him is going about their business with such supreme confidence? Chelsea now have 30 more points than at the corresponding stage last season and the only minor irritation for Conte was the stoppage-time goal from Manuel Lanzini that briefly gave West Ham hope of an improbable feat of escapology. For Chelsea, however, that was only a minor irritation. Hazard had opened the scoring with a classy breakaway strike and Diego Costa's 18th goal of the season, early in the second half, left an air of inevitability over the rest of the evening. Chelsea threatened all night with their quick, high-quality counterattacking. They do it better than any other team in England and in those moments, with Hazard driving forward and Pedro adding his own stylish touches, it was thrilling to see. José Mourinho likes to say his old team operate with defensive tactics but, in reality, there is much more to Chelsea than that. They sit back and then they spring forward. Costa's goal came from a corner but Chelsea were at their most dangerous when they broke from their own half and it was risky of West Ham to leave themselves so vulnerable this way. Slaven Bilic's side had nine men forward when Chelsea streaked clear to score the opening goal and that is bordering on reckless when their opponents are so devastating on the break. Chelsea demonstrated in those moments that counterattacking football can be exhilarating. N'Golo Kanté, the master of the dirty work, had cut out Robert Snodgrass's pass and in the following eight seconds the ball moved 75 yards, finishing in West Ham's net. Hazard's one-two with Pedro was weighted perfectly and in the course of three passes the home side had been split down the middle. It was a blur of speed and movement and, at the end of it, there was a wonderful touch of composure from Hazard to swerve round the goalkeeper, Darren Randolph, and slide his shot into the exposed goal. That was far from the only occasion when the speed and directness of Hazard and Pedro threatened on the break. West Ham lost their shape too easily and there was a lesson here for every team that faces Chelsea. It is that when Conte's side are defending, sometimes they are at their most dangerous. On that front, West Ham could probably be forgiven for feeling emboldened about the way they began the match. Andy Carroll was left with a bloodied face, having clashed heads with Victor Moses, on the first occasion when one of his team-mates tried to pick him out in the penalty area. With the game goalless, a succession of crosses was aimed Carroll's way, causing anxiety in the visitors' penalty area. Chelsea took their time to start playing like champions-in-waiting but they were always the more rounded side once they had the lead, scoring with their first attempt at goal, and might have doubled their lead before half-time after another breakaway finished with Costa narrowly missing Hazard's cross, Moses firing in a shot that ricocheted off Aaron Cresswell and Pedro's follow-up effort being turned away by Randolph. West Ham had lost their early momentum and, five minutes into the second half, they conceded a second goal. This one came from Cesc Fàbregas's corner and the inability of anyone in claret and blue to clear the danger inside the six-yard area. Pedro Obiang went up for the ball, in close proximity to Carroll, but succeeded only in flicking the ball behind him and Costa charged in to score off his thigh. Maybe the complexion of the night would have changed had Moses not been handily positioned to turn away a goal-bound shot from Sofiane Feghouli just after the hour. Yet West Ham now had the dilemma of needing a way back into the contest while also knowing that if they pushed too many men forward it would be playing into Chelsea's hands. Unfortunately for them, by the time Lanzini fired a low shot past Thibaut Courtois it was the second minute of stoppage time and the final whistle sounded before Bilic's side could muster another chance.