Both sides have won the competition five times apiece in the past - a tally only Liverpool can beat - but there was a massive gulf between them when they met in the Premier League just two weeks ago, with Man City running out 6-0 winners on that occasion.
Sunday could prove to be a make-or-break moment in the managerial career of Maurizio Sarri at Chelsea, with pressure continuing to grow on the Italian boss.
Fixtures against Man City have provided both the zenith and the nadir of his time at Stamford Bridge so far, inflicting a first defeat of the season on Pep Guardiola's champions back in December but then suffering utter humiliation at the Etihad Stadium earlier this month.
Anything close to a repeat of that infamous 6-0 drubbing may be enough to see the sword fall on Sarri, whose refusal to tweak his tactical style is a growing source of frustration amongst the supporters.
Sarri need only look across the dugout to Guardiola for an example of a recent Premier League manager who also resisted pressure to alter his football philosophy amid first-season questions, although not too many Chelsea supporters would expect their current boss to lead them to the heights Guardiola has done with City.
A 3-0 win over Malmo on Thursday night confirmed Chelsea's place in the last 16 of the Europa League but did little to lessen the pressure on Sarri's shoulders, coming as it did just three days after their FA Cup exit at the hands of Manchester United.
That loss came at Stamford Bridge, but it is away from home where their main problems have arisen recently, with four successive defeats on the road in domestic football, during which time they have conceded 13 goals without scoring once.
Sunday's match is on neutral territory, of course, but their recent record when leaving the Bridge does not bode well and Chelsea have already lost three times at Wembley this season - in the Community Shield against Man City and twice against Tottenham Hotspur.
What was once such a successful ground for them has become something of a bogey destination since their FA Cup triumph last season, then, and should that trend continue then it could be more than just silverware on the line.
Defeat would not come as a surprise to most, but the manner of it could prove telling for Sarri's future - if they meekly surrender as they did at the Etihad Stadium then Chelsea's notoriously trigger-happy board might be forced into action.
Victory, however, may just be enough to stave off the looming shadow of proposed successor Zinedine Zidane and bring a positive end to a difficult week for Chelsea which has seen them hit with a two-window transfer ban.
It would also provide the Blues with their first League Cup crown since 2015 and Sarri with the first major trophy of his career, having fallen just short on a few occasions during his time with Napoli.
It is worth noting that Chelsea have had a difficult route to the final too, beating the likes of Liverpool, Tottenham and Bournemouth already, so despite their recent struggles they have very much earned another Wembley appearance and will be desperate to atone for what happened at the Etihad two weeks ago.
Recent EFL Cup form: WWWLW
Recent form (all competitions): LWLWLW
Come kickoff at Wembley, Man City could be just 90 minutes away from ticking off the first leg of a potential quadruple.
Guardiola has played down the prospect - and even the possibility - of achieving the unprecedented clean sweep, but his side look very well placed to go one better than the treble their local rivals Manchester United managed 20 years ago.
City currently sit top of the Premier League table, face lower-league opposition in the quarter-finals of the FA Cup and boast an away first-leg lead in the last 16 of the Champions League, so further progression on all fronts looks likely.
The champions are also big favourites to come out on top against Chelsea on Sunday, due in a large part to the way they dismantled the same opponents so easily a fortnight ago.
Of course, Guardiola will be expecting a much stiffer test this time around, and the fact that his side were 4-0 up inside 25 minutes at the Etihad will not have made him forget that they were also beaten by Chelsea in December.
City come into the match in scintillating form, though, winning 13 of their last 14 outings across all competitions and scoring 18 goals during an ongoing run of five successive victories.
There could be a slice of club history for the Citizens on Sunday too as they aim to retain a trophy for the first time in their history - a feat they are also looking to achieve in the Premier League this season.
That title tussle with Liverpool must take a back seat this weekend, although the players will no doubt have one eye on events at Old Trafford when Liverpool face bitter rivals Manchester United just before City kick off against Chelsea.
Liverpool and United are, incidentally, two of only three teams to have retained the League Cup in the past, along with Nottingham Forest, so Man City will be aiming to join that exclusive club this weekend.
The English champions have only lost one of their previous six finals in this competition, and in terms of recent history they have dominated the League Cup like no-one else - victory on Sunday would hand them a fourth title in the last six years.
Such a record shows that Man City take this competition seriously, despite others being higher up the priority list, although they have had a comparatively kind route through to the final this term, beating Oxford United, Fulham, Leicester City and Burton Albion to reach Wembley.
It is a stadium they have already won twice at this season, and should they make it a hat-trick then the 'impossible' task of a quadruple would become that little bit more attainable.
Recent EFL Cup form: WWWWW
Recent form (all competitions): LWWWWW
The likes of Eden Hazard, Gonzalo Higuain and Jorginho - the latter of whom was booed by his own supporters when coming on against Malmo - are all expected to return after being left out of the starting XI on Thursday.
Jesus has scored more EFL Cup goals than any other player this season, although even if he is passed fit Sergio Aguero is expected to lead the line having scored 13 goals in 16 appearances against Chelsea, including a hat-trick two weeks ago.
Chelsea possible starting lineup:
Caballero; Azpilicueta, Rudiger, Luiz, Alonso; Kante, Jorginho, Barkley; Willian, Higuain, Hazard
Man City possible starting lineup:
Muric; Walker, Otamendi, Laporte, Zinchenko; De Bruyne, Fernandinho, D Silva; Bernardo, Aguero, Sterling
Head To Head
This will be the fourth meeting between these two sides already this season, with Man City winning two of those including one at Wembley in August's Community Shield.
It is the first time they have ever met in a League Cup final, though, and only the second time they have faced off in the final of any competition other than the Community Shield - after the 1985-86 Full Members Cup final which ended 5-4 in Chelsea's favour, still the highest-scoring final in Wembley history.
These two sides have not met in this competition since 1993-94, when City edged to a 1-0 win in the third round - one of only two previous League Cup editions of this fixture.
We say: Chelsea 0-2 Man City
It would be a damning indictment for Chelsea if they lost in a similar manner to the league game between the two sides earlier this month, but it would also be a significant surprise if they were to avoid defeat altogether. Almost everything points towards a Man City win, and it is hard to look past the holders on current form.