Arthur Masuaku’s freak goal earns impressive West Ham derby win over Chelsea

West Ham 3-2 Chelsea: In a game full of mistakes it was the Blues who made the most as David Moyes’ Hammers continued their sensational rise

Chelsea goalkeeper Edouard Mendy fails to keep Masuaku’s mis-hit cross out (Reuters)

A glitch in the matrix. Chelsea’s system fails at the source, as West Ham United revitalise their faltering push for the top four.

The very nature of the campaign also made it a huge day in the title race, even this early, although Chelsea may well point to the number of fixtures catching up with them. Many will inevitably point to the goalkeeper, Edouard Mendy.

It is the sort of thing football always throws up. Just at the point when Mendy was being talked up as the best goalkeeper in the world, and someone worthy of the Ballon d’Or next season, he had what felt like his first poor game for the club.

Mendy had a hand, almost literally, since one error came from his feet, in all three of the goals Chelsea conceded in this 3-2 defeat to West Ham. Arthur Masuaku’s mis-hit cross going in felt a fitting final touch to a game characterised by errors. It is certainly a slip by Chelsea, given that West Ham finished the game without their entire first-choice back four.

An infuriated Thomas Tuchel will hope it is little more than an off-day, an inevitable consequence of such a congested schedule. That is emphasised by the fact this was the first time that Chelsea had conceded more than once in a game in any competition this season, and just the third time in the German’s entire time at the club.

But it felt like there was a bit more to it than that, not least West Ham’s hugely creditable resolve under David Moyes.

Tuchel does have training ground work to do on the attack, as much as the defence.

Chelsea paid the price here for still not displaying the full value of their forward line.

That is emphasised by one pointed stat: defenders are now responsible for 41.1 per cent of Chelsea’s goals this season. You can call them efficient, of course, but it always feels they’re threading a line. It meant they were virtually certain to lose top spot, having squandered what had been a five-point lead.

It sums it up that this defeat wasn’t because of squandering chances. This is what happens when the defence falters, because Chelsea have become so dependent on it. Their attack hasn't yet been fully released, at least in contrast to their two rivals.

It was duly their lead defender that opened the scoring, through that manner most beloved of centre-halves: the header from a set-piece. West Ham had already had due warning when Thiago Silva saw one effort deflected wide, only to be left to attempt the same again. Hakim Ziyech whipped the ball across, and Silva headed in.

Mason Mount scores Chelsea’s second goal (Getty Images)

There were some questions about how it got past Lukasz Fabianski so easily, which was the same for Chelsea’s second.

Ziyech again sent an arched ball across, although this time from the corner of the 18-yard-box, and Mason Mount guided a volley into the space right by the post. It was superbly placed, but not exactly thunderous.

The let-off for Fabianski and West Ham was that there were to be bigger questions at the other end.

For the initial equaliser, it was a case of who was more at fault, Jorginho or Mendy? Both played their part, although due credit must be given to Jarrod Bowen. He was alert to Jorginho’s badly under-hit backpass, but the mystery is why Mendy didn’t just smash it away.

It is often the way of these things.

Mendy had been performing so flawlessly of late that his Shakira-themed song could be heard everywhere, naturally making a dropped note inevitable.

There is a theory in football that once goalkeepers make that first big error they make a string of them, and this match lent credence to that, even though Mendy has recovered from slips before. The first here wasn’t even a slip.

Mendy willingly went to ground as Bowen intercepted his attempted pass, although in a manner that suggested he’d never made a tackle before.

It was the most obvious penalty possible. Manuel Lanzini smashed it into the corner.

Bowen’s eventual equaliser in the second half had similar power but not quite that accuracy. As with Fabianski, it felt like Mendy could have got there.

Lukasz Fabianski collects a loose ball (Getty)

He was left stranded for one tantalising ball across the box by Michail Antonio but Bowen just couldn’t reach it quickly enough.

That was one of those classic chances that came on the break from Chelsea actually stepping up, as they went into their best attacking spell of the game.

This is where the questions come in about intensity, and the integration of the attack. It was only at 2-2 and with 20 minutes to go, as well as Romelu Lukaku on the pitch, that they really started to create.

As was the nature of the game, it just meant more space had been created in behind, and it led to unintended consequences.

It is certainly doubtful whether Masuaku actually intended that cross. It didn’t matter, though.

All that mattered was that, as with much of the game – in what was quite a rare occasion – Mendy couldn’t stop it.

The system broke down at source, and it means Chelsea fall from the top of the table.

Even the winner itself was a mistake. Chelsea can scarcely afford any more in a title race like this.