The Blues had been hoping to return to winning ways in the top flight after they suffered a 2-1 defeat by Manchester City in the Premier League last weekend.
However, Aaron Cresswell ended up scoring the only goal of the game for the visitors in the 48th minute as the Hammers sealed a famous win against their London rivals.
Chelsea FC dominated possession with 66 per cent and had 19 shots, six of which were on target, but they were unable to find the breakthrough against Manuel Pellegrini’s men.
Speaking after the game, Lampard admitted that his side needed to do more in the final third.
Lampard told his post-match news conference at Stamford Bridge: “We were below par in many parts of our game, it’s not one, but we didn’t do enough in the final third.
“That’s been a little bit of the story in our last three games. They were different, with Man City we got in the final third a lot and didn’t do quite enough with our choice of pass or cross or shot, similar to Valencia.
“Today we didn’t get in there quite as much, but we need to be more inventive and generally we have been this season.
“My gripe this season has been more that we’re not converting enough of the chances that we’re making. Today wasn’t quite that, we didn’t quite create enough.”
The Blues are yet to win a single point from a losing position in the Premier League this season, having lost all four games in which they’ve fallen behind this term.
Chelsea FC do not have long to dust themselves down as they turn their attentions towards their preparation for their home clash against Aston Villa in the Premier League on Wednesday night.
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