Chelsea make the short trip to face the Hornets having suffered a surprise 1-0 defeat at home to Leicester City on Saturday afternoon.
Watford have endured a topsy-turvy campaign with unbeaten streaks being followed by periods without a victory, but boss Javi Gracia will be delighted with where the club find themselves heading into Christmas.
The Hornets are not realistic contenders for a top-six finish come the end of the season, but they currently head the best of the rest despite having sold their best player during the summer.
There is still over half of the season remaining, and Gracia will not get carried away with a return of 27 points from 18 matches, although there will be an acknowledgement behind the scenes that Watford will never have a better chance of a top-half finish in the Premier League.
That has not been earned since ninth position was achieved in the old Division One back in 1987, and expectation levels are continuing to rise with Gracia overseeing a talented squad at Vicarage Road.
Watford were underdogs to gain a result away at an in-form West Ham United on Saturday afternoon, but a win and a clean sheet at the London Stadium has set the team up perfectly for the visit of an inconsistent Chelsea outfit.
The defence remains an issue with just four league shutouts being achieved all season, but goals and assists are coming from all areas of the pitch at a time when Watford are playing an exciting style of football.
Gerard Deulofeu is emerging as one of Gracia's key men having now found his feet after missing the opening weeks of the campaign, and the Spaniard has two goals and an assist from his last two appearances.
There will no doubt be interest in some of Watford's players during the January transfer window but if Gracia can ward off any approaches for Deulofeu and several of his teammates, there is no reason why the Hertfordshire-based club cannot build on what has been a promising four-and-a-half months.
Recent form: LLLDWW
Maurizio Sarri has received plenty of praise for the style of football which he has introduced since his arrival at Chelsea in July, but doubts are beginning to emerge in the stands regarding the Blues' progress on the pitch.
Chelsea were superb in registering a 2-0 win over Manchester City at the start of December, but the club have now suffered three defeats in six top-flight contests and are already effectively fighting for fourth place in the standings.
There will be an acknowledgement that Sarri has only been in his current position for little over five months, but a lengthy unbeaten streak has been followed by cracks beginning to appear in many areas of the pitch.
Chelsea have not scored more than two goals in a Premier League match in seven attempts, and neither of the team's two centre forwards or three central midfielders are contributing in the final third on a consistent basis.
That has resulted in calls for English trio Ross Barkley, Ruben Loftus-Cheek and Callum Hudson-Odoi to be provided with more regular opportunities but so far, Sarri is showing little sign of ditching what has become an established first XI.
Nine players have started in at least 15 of Chelsea's 18 league games this season, while Barkley and Loftus-Cheek have been provided with just six starts between them despite producing three goals apiece.
Sarri is likely to stick with his tried-and-trusted philosophy, but defeat at Watford would represent a fourth domestic setback in little over a month and the Italian would begin to come under pressure.
Chelsea's upcoming schedule is favourable, but Sarri will be aware that his side must take advantage with tougher games to come during a time when the club will be also attempting to win the Europa League, for both the glory and to try to guarantee qualification for next season's Champions League.
Recent form: LWLWWL
Recent form (all competitions): LWDWWL
Sarri is likely to hand a recall to Olivier Giroud, with the Frenchman having only been used off the bench against the Foxes.
Barkley or Loftus-Cheek should be handed an opportunity with Mateo Kovacic dropping out, while changes at the back are possible due to the upcoming schedule.
Gracia could keep the same team which got the better of West Ham, providing that he does not have to contend with any late injury issues.
Tom Cleverley is back in contention for a starting role, however, with the Englishman having come through the final 15 minutes against the Hammers after recovering from a long-term injury.
Watford possible starting lineup:
Foster; Femenia, Kabasele, Cathcart, Holebas; Capoue, Doucoure; Sema, Pereyra; Deulofeu, Deeney
Chelsea possible starting lineup:
Arrizabalaga; Azpilicueta, Luiz, Cahill, Alonso; Kante, Jorginho, Barkley; Pedro, Giroud, Hazard
Head To Head
The encounter on Boxing Day will represent just the 34th competitive clash between the sides, with Chelsea registering 17 wins in comparison to 10 victories for Watford.
Fourteen of those matches have taken place since the start of the new millennium, and Chelsea had put together a 13-game unbeaten streak heading into last season's corresponding fixture.
However, Watford ran riot against the Blues back in February and managed to prevail by a 4-1 scoreline.
We say: Watford 2-2 Chelsea
Watford have had no problem scoring goals this season, nor have they managed to put together a run of clean sheets. That should make for an entertaining spectacle and with Chelsea needing a positive response after the setback against Leicester, we expect the teams to share the spoils.