Maurizio Sarri maintained Chelsea remain a work in progress after they stumbled for the first time this season.

Sarri's 100 per cent record as Blues boss came to an end after a goalless draw at West Ham.

Not even Eden Hazard, back in the side after being rested in Europe in midweek, could find a way to break the deadlock.

It could have been worse for Chelsea had Michail Antonio and Andriy Yarmolenko converted extremely presentable chances for the Hammers.

Sarri said: "We need to move the ball quicker and we need more movement without the ball.

"We are improving in the defensive phase, but we have to improve in the offensive phase, especially in this kind of match.

"I knew West Ham were a very good team and I don't know why they lost their first four matches.

"They are really a very good team and they are now playing with confidence after they won at Everton last week.

"I think we have played well in the second half, but it's impossible to win every match and a point is OK."

West Ham were barely recognisable from the shambles of their first four matches, playing with more than a hint of shape and organisation as well as with plenty of attacking intent.

Antonio was denied by a point-blank save from Chelsea goalkeeper Kepa Arrizabalaga with his thigh at the near post in the first half but the miss of the match was Yarmolenko's.

The face of injured forward Marko Arnautovic in the stands said it all as Yarmolenko planted a free header, five yards out and with the goal gaping, wide of Kepa's left-hand post.

"Maybe it seemed easier to score than miss. Maybe he relaxed a bit more," said Hammers boss Manuel Pellegrini.

"It's a first clean sheet, against a team who have scored 14 goals, so in that respect I'm happy.

"But when you have chances against big teams you must score them. The draw is not a bad point but if we took those chances we could have got three."