West Ham 1-0 Chelsea: 3 lessons learned by Conte after latest defeat

In the weekend's first Premier League fixture, defending Premier League champions Chelsea fell to a shock 1-0 defeat by David Moyes' West Ham side at the London Stadium.

Marko Arnautovic's curled finish beyond Thibaut Courtois after just six minutes was enough for the Hammers, who defended well as a collective unit and were made to work hard too.

Antonio Conte will undoubtedly be frustrated with his side's inability to penetrate their opponents in the final third with much regularity. As a result, they remain 11 points behind leaders Manchester City - who can extend the gap further with a game in hand against arch-rivals United.

The defeat will give Conte some food for thought going into a testing run of fixtures. Here are three key lessons to be learned from this loss.

#1 The Blues cannot rely too much on Hazard and Morata

Eden Hazard and Álvaro Morata have been Chelsea's star players so far this season, but is there too much reliance on the pair?

Between the pair, Hazard and Morata have scored 14 and created 36 chances in the league this term

As seen against the Hammers, when the duo are having an off day, there are not many players who can step up and win them points.

Morata had a couple of opportunities to score but it just wasn't his day. The worrying thing is a lack of a goalscorer that Conte trusts to come on from the substitutes' bench.

Michy Batshuayi, a natural forward, was an unused substitute on this occasion but both Willian and Pedro were introduced - to no effect.

#2 Conte was too hasty to freeze out Diego Costa

West Ham United v Chelsea - Premier League

Following on from the first point, Diego Costa would have been the perfect player for Conte to utilise in this fixture.

The 29-year-old Spaniard, who is set to make his Atletico Madrid return next month, has the ability to single-handedly win matches - something he did regularly the last term to help drive the Blues to another Premier League triumph.

With strength, speed and determination in front of goal, he could have been a game-changer from the bench at the London Stadium. It appears as though Morata's backup options are not good enough for a team who have lofty title aspirations.

Another aspect of Costa's repertoire which Chelsea have missed in recent months, especially here, was his aggressive style. Morata and Hazard were both effectively dealt with by the hosts, who are physically stronger than the pair.

Costa would have provided a target to aim at inside the area while hassling the Hammers' backline - something that Morata struggled to do throughout.

There is no real debate that Costa is a more clinical finisher in comparison to his compatriot and Conte may potentially regret the harsh treatment he had for the no-nonsense forward.

#3 Tiemoue Bakayoko is yet to settle well in English football

West Ham United v Chelsea - Premier League

When Bakayoko signed for Chelsea from Monaco this past summer, it seemed that Chelsea were just going from strength to strength.

However, the talented Frenchman has failed to adapt quickly to life in English football and was hauled off at the interval by Conte. The defensive-minded midfielder seems the total opposite to N'Golo Kanté - sloppy in possession, lazy when marking and generally lacked confidence in attempts to actually take the game to the Hammers.

This could be because he does not suit Conte's current system with three central midfielders. He thrived under Leonardo Jardim because he had extra protection from Fabinho who was constantly sitting behind him in a deep midfield role, meaning he had the freedom to roam across the pitch.

However, at Chelsea, he either has one or two midfielders beside him, meaning his space in which to move is limited to one area of midfield.

It will ultimately take him more time to settle before he can live up to the £40m price-tag, which might not happen if he continues to only play in this system deployed by Conte.