The odds are stacked massively in their favour, but as we saw earlier in the season, it is possible to be the underdog and beat Manchester City; as proved by Crystal Palace in December.
The Sky Blues have an immense record in 2019, dropping only 3 points since the turn of the new year - in a shock 2-1 defeat at St. James' Park. Across the entirety of the season, they've won 23 out of 29 of their league matches; with four defeats and two draws from the games they haven't won.
Last week, City returned to the top of the Premier League as they beat a defensive Bournemouth side by just the one goal - courtesy of Riyad Mahrez - while fellow title-chasers Liverpool were held to a 0-0 draw at Merseyside rivals Everton.
It's also been a very positive start to the year for Watford. A late Andre Gray goal gave the Hornets a 2-1 victory over Leicester to ensure that the 5-0 defeat at Anfield in mid week had just been a slip-up.
That being said, whilst Watford's form against teams outside the top 6 has been immense, their form when facing teams inside that illustrious bracket hasn't been as good. That loss against Liverpool means that it is certainly likely that they could lose by a similar margin this evening. But who knows - Javi Gracia's men very nearly took all three points off Tottenham Hotspur in late January.
Between the two sides, the odds are also stacked in City's favour, with the Manchester side being the only team that Watford have failed to register a win against - nor a point - since their return to the Premier League in 2015.
Manchester City's big issue is with Kevin De Bruyne, who suffered a hamstring injury last week in what has become an injury-plagued season for the Belgian midfielder.
John Stones and Fernandinho remain sidelined whilst Aymeric Laporte could return.
For Watford, Javi Gracia has a full squad to choose from - which he'll no doubt need - as both Kiko Femenia and Sebastian Prodl return.
The Managers' thoughts
Pep Guardiola, like many other managers, was full of praise for Watford's man in charge, Gracia saying: "It's incredible what he has done, they have everything - incredibly organised, the manager is incredible what he has done this season."
"It's the last game before 21 days without the Premier League, before the international break. At home it's massively important for us to take our points."
Gracia also spoke well of Guardiola's team: "You know City have high-quality players, a very good squad and maybe you have to do perfect defensive work."
"You have less possession than them, for sure, and you have to manage your possession to create some chances to score. Do very good defensive work and at the end, if you do it, you have some good options to get a good result."
It seems as though the Hornets boss is ready for little opportunity - which means Watford must be clinical, more than ever before, if they wish to get anything from this tough away trip.