In a repeat of the 2007 showpiece - the first to be held at this ground - both sides know the importance of victory at the end of a disappointing campaign.
While United can argue that finishing second in the Premier League marks a vast improvement on the previous four years since Sir Alex Ferguson's retirement, Antonio Conte has far less ammunition to use when holding talks over his future next week.
Conte's second season in West London has not gone quite to plan, finding himself under pressure ever since the first game when Burnley picked up a shock 3-2 win at Stamford Bridge, setting the tone for what was to come for both sides.
Throwing away top spot in the Champions League and subsequently being knocked out by Barcelona in the first knockout round was difficult to take, particularly on the back of failing to turn up across two legs against Arsenal in the EFL Cup semis.
Yet in finishing fifth in the Premier League, collecting 23 points fewer than in 2016-17, Conte will surely have little to complain about if ruthless owner Roman Abramovich swings the axe as expected in the coming weeks.
Even if Chelsea were to win an eighth FA Cup, it remains to be seen whether the former Juventus boss would want to stay on. Conte has constantly provided subtle - and not-so-subtle - hints that he will be on his way this summer regardless of events at Wembley.
What better way to bow out than by lifting a second major honour in English football, then, a year on from a hugely disappointing 2-1 defeat at the hands of Arsenal in the final - a rare low point in the Italian's maiden campaign on these shores.
Four of Chelsea's seven previous triumphs in this competition have come in the last 11 years, beginning with an extra-time win against United in the first final to be held at the revamped national stadium, but they have not walked up the famous steps since 2012.
The way the Blues ended their league campaign suggests that their wait may go on, following up a four-match winning run with a draw to Huddersfield Town and 3-0 loss to Newcastle United on the final day, seeing them finish five points adrift of a Champions League spot.
Chelsea have not always been at their best in the FA Cup, either, most notably struggling to shake off Norwich City at the second attempt in round three, but victory in their final match of the season will ensure that a poor campaign suddenly looks slightly better.
Recent form in FA Cup: DWWWWW
Recent form (all competitions): WWWWDL
Among the numerous sub-plots ahead of Saturday's game, the most intriguing is surely Jose Mourinho's latest battle with Conte on the touchline - possibly the final chapter in a long-running saga.
Mourinho has the upper hand on Conte by virtue of finishing as runner-up in the top flight, adding to the EFL Cup and Europa League crown gained last season, and he will take great delight in being the one to strike the killer blow in Conte's Chelsea reign.
Ending 19 points adrift of Manchester City is hardly cause for celebration, though, and Mourinho therefore needs the FA Cup to ensure that he has United supporters firmly behind him ahead of a big summer of transfer activity.
The Red Devils' most recent success in this competition, when edging out Crystal Palace 2-1 two years ago, famously brought down the curtain on Louis van Gaal's underwhelming tenure. A similar outcome this weekend is unlikely, with Mourinho still very much the best available option for United.
A campaign that began nine months ago with defeat to Real Madrid in the UEFA Super Cup, taking in 55 games since then, finally concludes this weekend and it remains difficult to ascertain whether the season as a whole can be considered a success.
Defeat to Brighton & Hove Albion - making it three losses to promoted clubs this term - and a goalless draw with West Ham United sapped any sort of positivity out of United's supporters, making the 1-0 win against Watford on the final day, as uninspiring as it was, all the more important to build some momentum.
A second FA Cup final triumph in three seasons, and a joint-record 13 overall - matching Arsenal's tally - would be the ideal way for Mourinho to prove that he remains a serial winner, even if his style of play has been questioned repeatedly throughout the campaign.
Their path to this stage has been straightforward enough, brushing aside Derby County, Yeovil Town, Huddersfield Town and Brighton without conceding a goal, before earning a 2-1 comeback victory over Tottenham Hotspur here last month.
United have already beaten each of their top-six rivals since the turn of the year, including Chelsea in the most recent league meeting, suggesting that Mourinho does still have the knack of picking up results exactly when it matters.
Recent form in FA Cup: LWWWWW
Recent form (all competitions): WWWLDW
United are still sweating over the fitness of star striker Romelu Lukaku, who only returned to training on Tuesday following more than two weeks out with an ankle injury.
The Red Devils scored one goal in three games during the Belgian's absence, highlighting his importance to the side, and Mourinho's attacking options may be further limited as Anthony Martial was left out of the squad to face Watford due to a minor problem.
That decision may also have a bearing on whether Chelsea go with three players in the forward line or use an additional midfielder, with Willian and Pedro battling for a start on the opposite flank to Eden Hazard.
Chelsea possible starting lineup:
Courtois; Rudiger, Christensen, Azpilicueta; Moses, Kante, Fabregas, Alonso; Hazard, Willian; Giroud
Manchester United possible starting lineup:
De Gea; Valencia, Bailly, Rojo, Young; Herrera, Matic, Pogba; Sanchez, Lukaku, Mata
Head To Head
This is the eighth time that United have faced off against Chelsea at Wembley, meaning that they have played the Blues more often here than any other side.
However, it is the first time that they have met at the national stadium since the 2010 Community Shield, which the West Londoners lost 3-1.
We say: Chelsea 1-1 Manchester United (1-2 AET)
Competing in their record-equalling 20th FA Cup final, Man United arguably have more momentum on their side thanks to their second-placed finish in the Premier League. Chelsea, in what could be Conte's final match in charge, are aiming to avoid back-to-back final defeats but have their work cut out on current form.