While the reigning Premier League champions enter one of their favourite competitions - at least in terms of success under Pep Guardiola - at this stage, the Hornets have already seen off MK Dons and Plymouth Argyle to set up a glamour tie.
Match preview
A competition that used to be a foregone conclusion during the earlier years of Guardiola's Man City reign, the top-flight champions are yet to add another EFL Cup crown to their tally since a remarkable fourth on the bounce - and their eighth overall - in the COVID-affected 2020-21 season.
The Citizens have swapped EFL Cup medals for shinier Champions League and Club World Cup accolades over the past couple f years, although they have evidently lost their knockout nous in this competition, only getting as far as the quarter-finals since the start of the 2021-22 season.
Guardiola's bid to regain EFL Cup supremacy last year memorably ended at this exact hurdle to Newcastle United, but not since 1987 have they suffered back-to-back third-round eliminations, and the high from the weekend's absorbing events may not have worn off a little over 48 hours later.
For over 45 minutes of Sunday's second half with Arsenal, the Gunners' 10-man low block appeared impenetrable, only for substitute John Stones to bundle home Man City's latest-ever Premier League goal on record in an engrossing 2-2 draw, one which keeps Guardiola's men at the summit while simultaneously ending their 13-match winning run in the top flight.
Erling Haaland's record-breaking 100th Man City goal preceded Stones's bedlam-inducing leveller - as well as Riccardo Calafiori and Gabriel Magalhaes's efforts in between - but the Scandinavian sensation will surely have to wait for number 101 as the hosts work with just one full day of rest.
Now under the wing of a man who briefly made his mark on the red side of Manchester, Watford travel to the Etihad having slightly lost their way under Tom Cleverley, who oversaw a magnificent start before the month of September brought a month of sorrow.
Indeed, the Hornets won each of their first five competitive matches under the ex-Manchester United midfielder, including a 5-0 dismantling of MK Dons and 2-0 win over Plymouth Argyle in the earlier EFL Cup rounds to reach the third round for the first time since the 2021-22 season.
However, that two-goal triumph over Plymouth on August 27 represents the Hornets' most recent win in any setting, as they have only taken a paltry one point from three Championship games this month, losing to Sheffield United and Norwich City either side of a home draw with Coventry City.
Saturday's defeat to Norwich was particularly chastening for Cleverley, whose side were swept aside 4-1 by the Canaries to leave them outside of the top six in eighth position, albeit still just one point outside of the playoffs at this early stage.
Both the September form book and head-to-head record makes for extremely grim reading for the Watford faithful. Since holding the Citizens to a 1-1 draw in 2017, the Hornets have lost each of their last 15 games against merciless Man City, conceding a staggering 58 goals at a rate of nearly four per game. If nothing else, the Hornets can at least expect 100-goal Haaland to be rested in midweek.
Manchester City form (all competitions):
W
W
W
W
D
D
Watford EFL Cup form:
W
W
Watford form (all competitions):
W
W
W
L
D
L
Team News
In what may go down as the most forgettable appearance of his career, Rodri went down twice in the weekend's draw, one after a fifth-second clash with Kai Havertz and then with an apparent serious knee injury, although City fans are anxiously awaiting news on his condition.
Despite Guardiola suggesting that Kevin De Bruyne (groin) could have been available for the clash with Arsenal, the Belgian - as reports suggested - was not in the matchday squad and should not be thrown back into action against second-tier opposition either. Oscar Bobb (leg) and Nathan Ake (thigh) are also sidelined.
A full 11 changes cannot be ruled out by the City boss, who could also plunder the club's Under-21s ranks to help fill his selection for Tuesday's game, where the highly-rated Nico O'Reilly could play a prominent role.
Meanwhile, Watford's efforts against Norwich were not helped by two early defensive withdrawals, as goalkeeper Daniel Bachmann and centre-back Francisco Sierralta were both taken off within just a few minutes of each other in the first quarter of the game.
It is still unclear how serious their issues are, but neither should be expected to appear at the Etihad given the quick turnaround, so backup goalkeeper Jonathan Bond and Ryan Porteous ought to be drafted into the XI as their replacements.
Kevin Keben (knee) is also out of contention for the Hornets, while striker Daniel Jebbison is cup-tied, having played for Bournemouth in the second round before his loan move to Vicarage Road.
Manchester City possible starting lineup:
Ortega; Lewis, Stones, Simpson-Pusey, Wilson-Esbrand; Nunes, Wright; O'Reilly, McAtee, Grealish; Foden
Watford possible starting lineup:
Bond; Morris, Pollock, Porteous; Andrews, Dele-Bashiru, Sissoko, Sema; Chakvetadze, Baah; Bayo
We say: Manchester City 2-0 Watford
Even with a full complement of changes and several young stars handed opportunities to impress, expect Man City's streak of scoring multiple goals in games against Watford to continue as the Citizens progress to round four.