West Ham United secured their first three points of the season last time out against Everton, with an impressive 3-1 victory at Goodison Park - firing them off the bottom of the Premier League table and out of the relegation zone
Manuel Pellegrini's side will now face league leaders Chelsea, who will be looking to make it six wins in a row at the London Stadium. Here's everything you need to know ahead of this London derby.
Both sides confident
Before last weekends encounter against Everton, Pellegrini shocked a few by claiming that his side was confident, despite having lost all of their first four Premier League games, although it was clear as soon as the Irons took to the pitch that this was indeed the case, with them playing fast-flowing football as well as being brave in possession away from home.
Now they have three points under their belt, Pellegrini's men will only be more confident, this added with the fact that they have won their previous two encounters with the Blues at the London Stadium means that it is likely that the league leaders won't be the only confident side going into Sunday's game.
As for Maurizio Sarri's side, the season has gone practically perfect thus far - five wins out of five in the league, off to a winning start in Europe, and start man Eden Hazard seemingly thriving in a new system, they seem a very hard side for anyone to stop thus far, and whilst the highly experienced Pellegrini will certainly have a game plan, the mix of their undoubted confidence and ability will make them strong favourites in this encounter.
Marko Arnautovic expected to return
One downside to the Hammers' victory last weekend was the injury to Marko Arnautovic, who was forced off with an injury to his knee, however, his Chilean manager is hopeful of a return for his starman for Sunday's game.
"Marko finished with a problem behind his knee,'" the West Ham boss stated at his pre-match press conference. "We will see if he is fit for Sunday. He played well against Everton and we hope he will recover."
Javier Hernandez is also doubtful whilst Jack Wilshere, Manuel Lanzini, Winston Reid and Andy Carroll will all miss out through injury.
As for Chelsea, who had their preparations for this encounter changed due to a delayed flight back from their UEFA Europa League opener against PAOK, Pedro is a major doubt after picking up a shoulder injury whilst Mateo Kovacic could also miss the trip across London with a minor injury.
Whilst these two sides have endured very different starts to life under their new managers, this matchup has been an even one as of late, with three wins a piece in this fixture over the past few years. This mixed with the fact that both sides looked good last time out in the league, as well as the home crowd undoubtedly behind the underdogs, this has the potential to be a thrilling London derby.