Thomas Tuchel Devastated Over Costly Mistakes Following Chelsea's Defeat To West Ham.

Chelsea were stunned by West Ham as they were handed a second Premier League defeat this season.

The Premier League leaders travelled across the capital this weekend knowing that a victory at the London Stadium would move them four points clear of title rivals Manchester City and Liverpool.

But costly mistake from Chelsea sees them lose 3-2 to the Hammers who staged a thrilling comeback to secure all three points at the London Stadium.

Goalkeeper Edouard Mendy was at fault for two of West Ham's three goals, including Arthur Masuaku's eccentric winner.

The Blues early dominance was rewarded in the 29th minute as they went ahead through Thiago Silva towering header, only for Mendy to bring down Jarrod Bowen in the area after controlling Jorginho's suicidal backpass, with Manuel Lanzini converting from the penalty spot to draw West Ham level at the London Stadium.

Mason Mount scored a superb volley and restored Chelsea's lead just before half-time, but it counted for nothing as Bowen blast West Ham's second equaliser early in the second half.

Masuaku's speculative cross in the 87th minute somehow found a way past Mendy in mid-air to seal the West Ham victory.

Now Chelsea have joined the list of star-studded teams that has been beaten by David Moyes' well-drilled side this season.

The Hammers had already ended Liverpool's long unbeaten run this season, also defeated Leicester and Tottenham, as well as knocking Manchester City and Manchester United out of the League Cup.

David Moyes men climb to number 4 on the Premier League table. 

"Truthfully, I didn't think we played that well, but to get those goals against a team that don't concede many is a great credit to the lads," Moyes said.

The defeat for Chelsea leaves them second in the League standings after Liverpool and City all top of the league at some point.

It was a big disappointment for Chelsea manager Thomas Tuchel who had previously had the team positioned at the top of the table since early October.

Speaking after the disappointing defeat at the London Stadium, Tuchel said;

"We need to admit we did too many crucial mistakes at the moment. That cost us a potential win against Manchester United and today as well," 

"If you want a result at this level you have to minimise mistakes. We talked about it before, it's obviously not helped."

"The decision making from Edouard is not the best in this moment, he is going through a bit of a rough period, I don't know why exactly, but he seems to have lost a bit of confidence," 

"West Ham's first goal brought him into a really awkward situation.

"Their third goal is a strange one but we could not finish our chances. We had to be more ruthless," Tuchel added.

"He could have saved the situation, he did not. You can turn it and twist it, but this is far, far away from blaming anybody.

"Every loss is a bump in the road. We need to play more accurate, more stable and reduce big mistakes."

Tuchel admitted that the team have not been the same since facing Man United, as they luckily defeated Watford in midweek.

"I didn't see our performance dip against Manchester United or today, it was enough to win the game," Tuchel said.

"We gave easy goals away, this is unusual - big mistakes that lead to big chances and easy goals. We've done this against United, Watford, and today.

"We are not good enough in the details at the moment. This is a game about details, I can only repeat myself. Without doing big mistakes, there's a big chance we win this game.

"The [title] race is not interesting at the moment, what is interesting is the next 90 minutes. We have to have the focus right, the attitude right, and to take care of the details because we are not good enough with the details at the moment.

"If you want to protect yourself against counter-attacks, it is impossible to do these kind of mistakes. We have done these three times in a row; this is simply too much."

Chelsea prepare to face Zenit in their Champions League last group stage game on Wednesday having secured qualification to the next round already. Their next league game is at home to Leeds United on Saturday as they hope to bounce back to winning ways.