Key stats
West Ham have conceded eight goals across their opening two games of a top-flight season for the first time in their history.
Chelsea became only the 10th side in Premier League history to score five goals or more in their first away game of the season. They were also the last to do so (winning 6-2 v Wolves last season).
Graham Potter is the first West Ham manager in the Premier League to fail to get into double figures for points in his first 10 home games (nine points - two wins, three draws and five defeats).
Highlights
Analysis
Joao Pedro was the highest-ranked player of the match with a score of 9.2, while there were five different goalscorers for the Blues that sent West Ham's goalkeeper Mads Hermansen's score plummeting to 4.8.
Match report
Enzo Maresca’s side were dealt a blow before a ball was even kicked, as Cole Palmer withdrew from the starting line-up due to an injury in the warm-up.
Their woes were compounded in the sixth minute when Lucas Paquetá fired home an absolute rocket with his left foot to put the Hammers in front, but the hosts’ defensive vulnerabilities soon came to the fore, allowing Chelsea to quickly restore parity.
Marc Cucurella flicked on Pedro Neto’s corner towards João Pedro to head home his first goal against West Ham.
A breathless opening 20 minutes looked to have taken another twist when Niclas Füllkrug rifled in a left-footed strike, but VAR chalked it off due to an offside call against Jean-Clair Todibo in the build-up.
That short-lived joy which cascaded around the London Stadium was soon forgotten, with Chelsea completing the turnaround in the space of 17 minutes through Neto.
The Portuguese was allowed to ghost into the box unmarked to volley home from Pedro’s cross, with the Hammers’ defence static and unalert to the danger.
Palmer’s replacement, Estêvão, was then the architect of Chelsea’s third goal, providing the cut-back for Enzo Fernández to tap in, and becoming the youngest player in PL history to assist a goal for Chelsea at 18 years and 120 days old.
Fernández should have added a fourth after Chelsea effortlessly carved open the West Ham defence once again, but failed to find the target on this occasion from Neto’s delivery from the left.
A fourth soon arrived, though, as Mads Hermansen made a hash of an incoming corner and Moisés Caicedo was on hand to punish the Dane’s error. Trevoh Chalobah added a fifth two minutes shy of the hour mark following the home side’s hapless attempts to clear the danger, as many Hammers fans headed for an early exit.
This seemed to prompt a response from the hosts, who carried a threat for the first time in the match with a flurry of activity in Chelsea’s box. Substitute Kyle Walker-Peters’ cross-shot was cleared away from the goalmouth by Caicedo, with the Hammers showing something resembling a response.
It looked like Chelsea were about to score their sixth moments later, with Reece James brilliantly picking out Estêvão, but the Brazilian’s effort took a deflection and Hermansen made a comfortable save.
Ultimately, it was a chastening evening for West Ham and Graham Potter, who has still never beaten Chelsea in eight managerial meetings (D4, L4).
And after only picking up nine points in his first 10 home PL games in charge, he broke an unwanted club record previously shared by Alan Curbishley and Avram Grant, who managed 10 in their first 10. As for Chelsea, they claimed their 33rd win in this competition against the Hammers, having only beaten Tottenham Hotspur more often (37), and for at least 17 hours or so, go top of the table.
Flashscore Man of the Match: Pedro Neto (Chelsea)
Post-match comments
Chelsea defender Marc Cucurella told Sky Sports: "We are very happy. I think in the last game we missed something. I think we don't play our style but I think today, at the beginning, we started a little bit sloppy but the reaction from the team was very good.
"We showed a lot of energy. We want to play good football and we have a good result tonight."
After losing Cole Palmer in the warm-up prior to the match, he said: "It's difficult because we practice one thing, at the end we need to change very fast. But I think Estevao, in this case, played an amazing game.
"I think it's very important because we have a good squad, all of us, we are ready at any time and we are very happy because we showed we have a good team."
West Ham captain Jarrod Bowen speaking to Sky Sports: "I think you can probably imagine. Fuming. Disappointing. All the emotions that come with being on the back of conceding eight goals in two games and not picking up a point yet.
"I think we got ourselves into a really good position at 1-0 and then I thought the goals were really cheap on our behalf. We didn't really make them work for those three from set pieces, which we've always prided ourselves on over the years and a couple more finishes inside the six-yard box.
"We gifted the goals away and you do that against any opposition and we've learnt that against Sunderland last week and here tonight."