Pep Guardiola's exhilarating City side followed up their magnificent 100-point Premier League-winning campaign of 2018 by playing even better to become the first English side to claim a domestic treble.
Yet they were pushed all the way to the league crown by Liverpool in a magnificent title race, eventually taking the prize by just a whisker – 98 points to 97 – after winning their last 14 matches.
Liverpool, who began the year leading the Premier League, lost just one match throughout the campaign but – critically – it came at the Etihad Stadium in January when John Stones made a dramatic clearance off the line with just 11mm to spare.
That small margin made a huge difference but, when it came to Europe, Jurgen Klopp's men were kings. While City's quadruple bid ended in agonising, VAR-related, last-gasp fashion at the hands of Tottenham, Liverpool produced another comeback for the ages to reach the final.
Trailing 3-0 to Barcelona after the first leg of their semi-final at the Nou Camp, the Reds produced arguably the greatest European night in Anfield's long history to fight back and prevail 4-3 on aggregate.
After that, the final against Spurs – who enjoyed their own dramatic semi-final fightback against Ajax – proved a damp squib. Mohamed Salah struck an early penalty and Divock Origi added a late second in Madrid to hand the Reds their sixth European title.
The Europa League final was also an all-English affair, with Chelsea beating Arsenal in what proved Eden Hazard's final match for the club before joining Real Madrid, and manager Maurizio Sarri's last hurrah.
Arsenal boss Unai Emery also failed to see out the year after a poor start to the 2019-20 campaign and a downturn in Spurs results led to the sacking of Mauricio Pochettino, who was replaced remarkably quickly by former Chelsea and Manchester United boss Jose Mourinho.
Sarri was succeeded by Chelsea's record goalscorer Frank Lampard, who had impressed by leading Derby to the Championship play-off final. Lampard was hampered by a FIFA-imposed transfer embargo but his decision to play youth was paying dividends in a bright start to his tenure.
Leicester enjoyed a resurgence under Brendan Rodgers but, as the year drew to a close, it was Liverpool setting the pace in pursuit of a first league crown in 30 years.
In Scotland, Celtic claimed their eighth successive title in a treble-wining season but Rangers, after years in the doldrums, were finally closing the gap under the bright stewardship of Steven Gerrard.
On the international front, England were beaten in the semi-finals of the Nations League by Holland but cruised through Euro 2020 qualifying, winning seven of their eight group games and scoring 37 goals.
The low point of the campaign came in Bulgaria, with a game needing to be stopped twice as England players were racially abused by supporters.
Wales also made it through to next year's tournament but Scotland, Northern Ireland and the Republic of Ireland will have to wait until the play-offs next spring to see if they are involved.