The race for a place in the top four and Champions League football is at stake. Chelsea will be hoping the likes of Eden Hazard will be on form to do the double of Watford.
Last Time Out
Last time out saw Hazard score his 100th goal for the club. The Belgian's masterclass helped the Blues win 2-1 at Vicarage Road back in December.
Chelsea went 1-0 up with half time beckoning. A left-footed drive from the Blues' number ten all but sealed the lead going into the break.
In the third added minute of the first half, Roberto Pereyra brought it back for the Hornets.
However, Hazard was not finished. To the rescue once again, the Belgian scored his 101st goal for the club - a trademark penalty.
The Blues have a proud record to fight for on Sunday. Chelsea have only lost to Watford once since the turn of the millennium (P15 W11 D3 L1).
However, not it's been easy. The Hornets have scored eleven goals in their last five games against the Blues, but only won once in that time.
Maurizio Sarri will be counting on his side to be clinical knowing his Chelsea side have conceded more goals than any other top four side.
Chelsea have only won one of their last five games in all competitions, two of which were crucial Europa League fixtures.
The last game, an important 1-1 draw away to Eintracht Frankfurt which saw Hazard start on the bench.
The Blues's recent Premier League form has been impressive. In their last five games - one loss to a title challenging Liverpool and a hard-fought 1-1 draw at Old Trafford.
The remaining three of the last five - the Blues arguably dropped two points with 2-2 draw to Burnley. However, victories over West Ham and Brighton & Hove Albion saw the Blues secure two clean sheets and six points.
What this means for the two clubs
A win for Chelsea would send the South West London club into third ahead of Tottenham Hotspur and prove crucial come the end of the season.
Sarri's mission for Champions League is all but over. A shot at the Europa League and in the running for top four, the Italian manager will want to all his side can to pick up three points.
A narrow win for Javi Garcia's side would send the Hornets above Leicester into ninth. However, in the unlikely event a 9-0 win for Watford would place them eighth above Everton on goal difference.
The Hornets have smashed their record points tally in a Premier League season (previously 45, now stand on 50) and will only look to better that record. Alongside a shot at the FA Cup against Manchester City, the Hornets will want to ensure they end the season well.
Hazard is expected to start against Watford having been started on the bench in the mid-week tie.
The Blues are running low at the back with Gary Cahill uncertain with an Achilles injury and Antonio Rudiger out for the remainder of the season.
Ruben Loftus-Cheek was substituted with ten minutes to go mid-week but remains in contention for a place in Sarri's eleven.
Kepa Arrizabalaga; Cesar Azpilicueta, David Luiz, Andreas Christensen, Marcos Alonso; N'Golo Kante, Jorginho, Ross Barkley; Willian, Gonzalo Higuain, Hazard