Chelsea endured a miserable start at West Ham, falling behind and losing talismanic midfielder Cole Palmer to injury, before hitting back to lead midway through the first half.
Palmer was seen jogging down the tunnel at the London Stadium prior to kick off, sparking fears the England international had sustained a problem and it was confirmed minutes later.
He was replaced by Estevao Willian, and the Brazil youngster was soon in the thick of the action. Estevao attempted a clever flick near the halfway line but was dispossessed by Lucas Paqueta and he ran unopposed before lashing a shot past Chelsea goalkeeper Robert Sanchez, who ought to have done much better.
It would have been easy for Chelsea to capitulate in a hostile atmosphere but instead they hit back.
Joao Pedro had already had a penalty appeal turned down after his run was blocked by Max Kilman but it was the former Brighton striker who dragged the Blues level after 15 minutes.
Pedro Neto whipped in a corner from the right, Marc Cucurella flicked it on at the near post and Pedro nodded past Mads Hermansen.
West Ham thought they had gone back in front but Niclas Fullkrug’s goal was ruled out for offside against Jean-Clair Todibo in the build-up and Chelsea rode their luck to score again.
Trevoh Chalobah won the ball off Paqueta with a rugged challenge which West Ham felt was a foul. The ball was picked up by Pedro and his cross to the far post was met on the volley by Neto, who had got in front of Aaron Wan-Bissaka.
