Yet on Saturday the clubs will meet in the competition's second all-English final in three years after emerging from bruising experiences with a stronger outlook.
For City, when the 2019-20 season resumed after its pandemic-enforced stoppage, their imminent surrender of their Premier League crown to Liverpool was not their biggest concern.
Off the field a far bigger battle was under way as the club took their appeal against a two-year suspension from European competition for breaches of UEFA's Financial Fair Play regulations to the Court of Arbitration for Sport.
Defeat would have been an obvious setback to their lofty European ambitions, throwing the futures of manager Pep Guardiola and key players into doubt and raising questions over their pulling power in the transfer market.
Yet it was a fight the club were always bullish about winning, adamant in their belief they had done no wrong. Their confidence was not misplaced as they were cleared in July and their ban was overturned.
When Guardiola, who had entered the final year of his contract, then committed to a new deal four months later, their Abu Dhabi-accelerated odyssey from Premier League also-rans to the top of the European game was back on the rails.
It is a journey they may have hoped would have been completed before now, with the Champions League knockout stages having become a source of recurring frustration in recent years, but their day of destiny could now be coming.
The season did not begin smoothly, partly due to the impact of the pandemic on the calendar, but Guardiola has shaped a magnificent campaign.
The Premier League and Carabao Cup are already in the bag and, until last month, a quadruple was even possible. They will more than happily now settle for a treble, though, that would further vindicate everything that has happened at the club since the takeover by Sheikh Mansour in 2008.
Standing in their way will be a Chelsea side whose own place in the showpiece game probably could not have been predicted last summer.
The Blues, having been hampered by a transfer ban the previous year, only qualified for the competition with victory over Wolves on the final day of the season in July.
Their start this term was then rocky and manager Frank Lampard paid the price in January, but their revival since under Thomas Tuchel has been impressive.
They may have gone off the boil since reaching the final, but they did reach the FA Cup final and finish fourth in the Premier League, both of which might have seemed optimistic when Lampard left. They have also beaten City twice in the past six weeks which, while not necessarily having a huge bearing, can only boost confidence for a game in which they are underdogs.
Tuchel has deployed a 3-4-3 system which has blended the better elements of the tactics played under Antonio Conte and Maurizio Sarri with his own style. Toni Rudiger, out of favour under Lampard, has returned as a pivotal figure and N'Golo Kante, who is battling to recover from a hamstring strain, has been outstanding at the base of midfield.
City are strong from back to front, with the arrival of Ruben Dias having transformed their defence and released the likes of Kevin De Bruyne, Phil Foden, Ilkay Gundogan and Riyad Mahrez further forward. With Sergio Aguero missing a huge chunk of the season the team have also learned to thrive without a specialist centre forward, particularly in European games.
The stage is set for a gripping contest.