Watford make the trip to Stamford Bridge having to rely on other results in order to remain in the hunt for seventh position.
Maurizio Sarri will be relatively satisfied that his side remain in contention to achieve their goals in two competitions at this stage of the campaign, but the Italian is still under pressure to rotate his squad effectively over the next week.
The Blues have squandered chances to have one hand on a top-four place in the Premier League table and one foot in the Europa League final, and it leaves Sarri having to commit to winning every match.
Sarri acknowledged that his side could have defeated each of Manchester United and Eintracht Frankfurt in their last two fixtures, although there were still positives to take from registering 1-1 draws at Old Trafford and the Commerzbank-Arena.
Earning a share of the spoils at United at least kept their rivals three points behind in the race for Champions League qualification, while Pedro's away goal in Germany has left the West Londoners in a position where victory in the second leg will set up a final against Arsenal or Valencia.
Sarri's biggest issues are coming in defence due to injuries to their centre-backs, and it has resulted in Chelsea now going five matches without keeping a clean sheet.
That will only provide Watford with encouragement ahead of their visit to the capital, but the Hornets would be naive to dismiss Chelsea's threat in the final third.
Pedro has not scored a Premier League goal since the end of February, but the Spaniard has netted four times in his last four outings in the Europa League.
Eden Hazard should also be well rested as he continues his pursuit of a 20th goal in all competitions this season, and the Belgian is due another having gone over 400 minutes without finding the back of the net.
Recent form: WWWLDD
Recent form (all competitions): WLWDDD
Watford have spent much of the season as one of the main contenders to finish in seventh place in the standings, but the Hornets must now rely on other results if they are to achieve their best-ever finish in the Premier League.
Four defeats in seven outings have resulted in Javi Gracia's men dropping down to 10th position, and it leaves Watford hoping that Wolverhampton Wanderers, Leicester City and Everton all drop points during their final two matches.
Watford will have a second chance to qualify for next season's Europa League due to their meeting with Manchester City in the FA Cup final, but Gracia will want his side to push for two victories in their closing league fixtures.
The Spaniard will feel that his players can take advantage of any tiredness in the Chelsea squad, while the final game at home to West Ham United also provides Watford with an opportunity to reach 56 points.
The biggest disappointment for Gracia will be having failed to defeat either Southampton or Wolves at Vicarage Road, and a win in either contest would have left the club as favourites to see off their nearest rivals.
Those results have come with Troy Deeney on the sidelines due to suspension, but the club skipper will be motivated to make up for lost time when taking to the pitch at Stamford Bridge.
Gerard Deulofeu is also ending the season in a good run of form, and the winger will hope to net his fifth goal in as many games if selected against Chelsea.
Watford will have to cut out individual mistakes at the back to give themselves the best possible chance in their remaining encounters, but Gracia's side have made a habit of hitting back from setbacks throughout this campaign.
Recent form: LWLWDL
Recent form (all competitions): WWLWDL
Sarri hopes to have Ruben Loftus-Cheek available after the midfielder suffered cramp against Frankfurt, but the England international is only likely to make the bench.
Gary Cahill remains a huge doubt to make the squad due to an Achilles problem, while Antonio Rudiger and Callum Hudson-Odoi will sit out the rest of the season after knee and Achilles surgery respectively.
Deeney will be provided with a recall to the Watford starting lineup, with Andre Gray expected to drop down to the substitutes' bench.
That could prove to be Gracia's only alteration, despite witnessing his team suffer defeat to Wolves last weekend.
Chelsea possible starting lineup:
Arrizabalaga; Azpilicueta, Christensen, Luiz, Alonso; Kante, Jorginho, Barkley; Willian, Higuain, Hazard
Watford possible starting lineup:
Foster; Janmaat, Mariappa, Cathcart, Holebas; Doucoure, Capoue; Hughes, Pereyra; Deeney, Deulofeu
Head To Head
Sunday's meeting will represent just the 35th competitive encounter between the clubs, with Chelsea registering 18 victories in comparison to 10 wins for Watford.
Chelsea have suffered just one defeat in 15 games against Watford, although the success for the Hornets came as recently as February 2018 when they prevailed by a 4-1 scoreline.
Two goals from Hazard proved to be enough for Chelsea when the teams met at Vicarage Road on Boxing Day.
We say: Chelsea 2-2 Watford
Chelsea continue to contend with a hectic schedule, and there will undoubtedly be tiredness in the squad ahead of this fixture. That could open the door for Watford to push Chelsea all the way, but we still expect the Blues to earn at least a share of the spoils.