Chelsea boss Antonio Conte has suggested that he was left impressed by West Ham United's win over Southampton last weekend.
The Hammers had endured a turbulent few weeks in the Premier League before the East London outfit ran out 3-0 victors over the Saints to boost their chances of survival.
The Blues play host to their city rivals on Sunday afternoon, and Conte has claimed that his first-team squad need to pay "great attention" to David Moyes's side.
At a press conference, the 48-year-old told reporters: "We must pay great attention. In the last period they are playing good football and getting good results and we must pay great attention.
"At the same time we want to get three points, it is a London derby and for us it is an important game to try to continue to have a hope to reach the place in the Champions League."
Chelsea head into the match having lost three of their last four fixtures in the top flight.