The Premier League giants have met on 13 previous occasions in the world's oldest domestic cup competition, including last season's final.
Eden Hazard scored the only goal of the game to decide that tight match at Wembley Stadium nine months ago, making it four successive wins for Chelsea in this cup fixture.
There has been little to separate the sides over the course of 2018-19, however, with United just a point better off than their opponents following their recent revival and Chelsea's downturn in form.
Ahead of Monday's match in West London, Sports Mole selects the strongest combined XI from both teams using only the players expected to be available for selection.
Out: Jesse Lingard (hamstring), Anthony Martial (groin), Marcos Rojo (knock), Marco van Ginkel (knee)
Doubtful: Matteo Darmian (knock), Antonio Valencia (muscular), Alexis Sanchez (knock), Danny Drinkwater (tendon), Ruben Loftus-Cheek (back), Gary Cahill (back)
Although he is expected to miss out on Monday, with back-up keeper Sergio Romero being preferred in the previous two rounds of the FA Cup, David de Gea remains the best all-round keeper in the Premier League. Clean sheets have been an issue for United all season, but the world's most expensive keeper Kepa Arrizabalaga has shipped 15 goals in his last four outings and improvement is needed if he is to move into the same bracket as his opposite number.
Cesar Azpilicueta is a pretty straightforward choice at right-back thanks to his reliable presence over a number of years for Chelsea. Ashley Young's age has started to tell this season, particularly against Paris Saint-Germain in midweek, and Antonio Valencia is now out of the picture ahead of his likely summer departure. On the opposite flank, Marcos Alonso often catches the eye but this 4-3-3 setup favoured by Maurizio Sarri often leaves the Spaniard badly out of position, whereas Luke Shaw is able to combine defence with attack, even if there is still room for improvement in both areas.
Centre-back has been a troublesome position for both teams this term, despite an array of riches to choose from. Ole Gunnar Solskjaer has chopped and changed between Chris Smalling, Phil Jones, Eric Bailly and Victor Lindelof, and it is the latter of that quartet who has looked the more solid over the past couple of months. Antonio Rudiger is a better defender than David Luiz, meanwhile, though he did have a bad game in the recent defeats to Manchester City and Bournemouth.
Sarri's experiment with N'Golo Kante in a right-of-centre midfield position has brought out the attacking side of the Frenchman's game that not many felt he had, but there is no doubt that he is better used in defensive midfield. That is where he is selected in this combined XI, meaning no place for Jorginho in the holding role - sorry Sarri! - and it is also an easy call using Paul Pogba on the left of the midfield three, where he has thrived under Solskjaer. It is then a choice between the likes of Ander Herrera, Nemanja Matic, Ross Barkley and Mateo Kovacic for the remaining midfield berth, which Herrera gets on the basis of his form in recent weeks and his ability to shuttle up and down the field.
Anthony Martial and Jesse Lingard are not in contention for a place in our hybrid side as they are both nursing injuries, and Gonzalo Higuain has to be shoehorned in through the middle, so Marcus Rashford is pushed out into a wide position. Despite some poor results for Chelsea, Higuain has shown some flashes of why he is so highly regarded by Sarri, while Rashford has struck eight times in 14 matches. The final spot in the side is a straightforward one, with Eden Hazard on course for his best season yet in terms of goals and assists.