Having just put a stop to a dreadful run of three consecutive defeats, the last thing Manchester United need is a trip to Stamford Bridge.
But they must have weaknesses, right? There must be some flaws United can expose...
Ahmed Elmohamady gets the better of Ashley Cole
Ashley Cole was the best left-back in the league for years, one of the best in Europe, but age catches up with everyone and the former Arsenal man is proof of that. Now he's 33 years old, his legs aren't what they used to be, meaning players he used to eat up for breakfast now get the better of him.
Last month, Jose Mourinho claimed that Cesar Azpilicueta, a right-back, was his first choice for Cole's position. However, with Branislav Ivanovic out injured, Azpilicueta will move to his preferred slot which means United have Cole to play with.
The problem with this area of weakness is United don't have a particular strength down the right wing. Rafael da Silva and Antonio Valencia have had some good games together this season, particularly away at Aston Villa, but Tony's form has been hit and miss.
However, Moyes has the option of playing Adnan Januzaj on the right wing, despite having spent most of the season on the left, and he could give Cole a terrible time. His pace would leave Cole for dead and his quick feet make the most experienced of defenders dizzy.
Fernando Torres, Samuel Eto'o and Demba Ba have eight Premier League goals between them this season, which is as many as United's third-choice striker, Danny Welbeck, has to himself.
Chelsea are blessed with many talented players, but when it comes to strikers they are scraping the barrel for talent. Their best forward plays for Everton!
All season long, Chelsea have been creating plenty of chances but they have struggled to finish games off. If United can, somehow, keep Hazard and Oscar's contribution to a minimum, their chances of conceding dramatically decrease.
David Luiz or Ramires are likely to play in midfield for Chelsea on Sunday with Frank Lampard out. The former is unpredictable and whilst he is capable of incisive passing to bring the forwards into the game, he is prone to the odd clanger or two. His tendency to try and intercept balls means he could be dragged out of position, if United's players are capable of luring him into that trap.
Ramires' passing is pretty poor and if he is played alongside Mikel, he will be expected to play a more attacking role, meaning Chelsea could struggle to get the ball forward if relying on his distribution. Neither Michael Carrick nor Darren Fletcher have the pace to keep up with him, but their positioning could lead to a fair few interceptions.
Relying upon full-backs for width is a bit dangerous for Chelsea if their attacking midfield trio is not firing on all cylinders. A compact opposition, intent on playing on the counter, can frustrate the Chelsea team.
Chelsea's full-backs rarely make it into the final third and their crossing ability isn't the best, which means United can attempt to defend narrowly and block Hazard and Oscar from having space.
Without Juan Mata, there isn't that magical eye for the defence-splitting pass in these types of games, if the performance from these teams at Old Trafford earlier this season is anything to go by.