United's lacklustre 0-0 draw against West Ham on Thursday was enough to secure their best league finish since Sir Alex Ferguson left the helm five years ago.
Jose Mourinho's men are limping towards the Premier League finish line, with defeats at Brighton and a goalless draw against West Ham leaving the United boss questioning the mentality of some of his players.
Watford secured their safety in the Premier League a while back, and have gone under the radar slightly in the last couple of weeks. Their impressive win against Newcastle last week was their first win in eight Premier League matches.
Mourinho has confirmed he will recall Anthony Martial and Marcus Rashford to the starting line-up, with Romelu Lukaku set to miss out through his ankle injury he picked up against Brighton.
Marouane Fellaini is set to miss out with a muscle strain, while Mourinho has said he will allow Michael Carrick to play in front of the Old Trafford faithful one final time before he hangs up his boots.
Younes Kaboul, Tom Cleverley, Tommie Hoba and Stefano Okaka all remain sidelined for the Hornets, while Andre Carrillo Diaz and Nathaniel Chalobah are in contention for a return.
It was just last season we saw a classic match-up between the two, as Watford blitzed United in a 3-1 victory at Vicarage Road.
Etienne Capoue scored his fourth league goal in five games to give the Hornets the lead before Rashford equalised shortly after. Watford restored their lead through Camilo Zuniga though, and Troy Deeney sealed the deal with a 90th minute strike from the spot.
The win was Watford's first over United since 1986, and represented a third defeat in a row for Mourinho - ensuring his worst run as a manager since his Porto days of 2002.
Paul Pogba vs Abdoulaye Doucoure
The two Frenchmen will go head to head in the centre of the park at Old Trafford, which could prove to be the most enticing battle on the pitch.
The two players have experienced two very different seasons. Pogba seems to be scrutinised with every touch, whilst Doucoure has earned all the plaudits including the 'Player of the Season' for Watford this campaign.
Two very similar players - tall, athletic, strong and fantastic on the ball. This will be an interesting match-up from start to finish.
Pogba has massively under-performed in recent games, and for most of the season in general, whilst Doucoure has been vital to Watford's impressive campaign.
With one eye on the FA Cup final for Manchester United, Sunday's match against Watford will be all about building positive momentum and giving Michael Carrick the send off he deserves.
Watford's win over Newcastle last week was their first win in eight games, and their poor form has only gone under the radar because their Premier League safety was secured a lot earlier than was expected.
Despite United's dull performances in recent weeks, they still remain defensively sound, with David De Gea winning the Golden Glove award this year with an astonishing 18 clean sheets.
Old Trafford has once again become a fortress this campaign, with only Manchester City leaving with all three points. Watford are unlikely to repeat that feat of the champions and they will lose here.
Prediction Manchester United 2-0 Watford