Match ends, Brighton and Hove Albion 1, Watford 0.
Pascal Gross struck the winner as Brighton earned their first Premier League victory in eight games - on the day Seagulls defender Connor Goldson played his first competitive game since heart surgery.
Goldson, 25, had preventative surgery in February after routine screening uncovered "a possible risk factor".
Seagulls boss Chris Hughton praised the centre-back as he played the full 90 minutes on his Premier League debut and was given man of the match by the stadium announcer.
"Someone who has not played for that period of time, to put in that kind of performance speaks volumes for him," Hughton told Match of the Day.
"The scare and what he went through last season is out of the way now.
"He has waited a long time to get the opportunity to play - everyone is so delighted for him."
German midfielder Gross broke the deadlock on 64 minutes as his shot from the edge of the box went under Watford keeper Heurelho Gomes.
It also ended Brighton's goal drought and was just the second time they have found the net in their past seven games.
Watford rarely threatened and the Seagulls should have been out of sight with Lewis Dunk and Tomer Hemed missing good chances.
The Hornets almost snatched an equaliser in the 94th minute as Brighton keeper Mat Ryan fumbled an Andre Carrillo cross but Stefano Okaka could only knee the ball wide from close range.
This was Watford's fourth league defeat in a row and their fifth in their last six games, while Brighton move to 12th, five points clear of the relegation zone.
Brighton get that winning feeling
Going into the match, a lack of wins and goals was the concern for Brighton.
Three draws and four defeats in their past seven matches had the Seagulls looking down the league at the teams below.
But they dominated the game, and winger Solly March impressed on the left of midfield, with 52% of their attacks coming down his wing.
Profligacy in front of goal seemed to be their main problem and Goldson missed a free header in the 31st minute.
The second half was going the same way until they deservedly took the lead, but Hughton will have wished in the closing minutes that the margin was more comfortable
"I felt the scoreline flattered them," Hughton told BBC Sport. "We need to take those chances, otherwise we will apply pressure on ourselves."
But he hailed the "big win", and with half the season now played, the Seagulls have 21 points, over halfway towards the 40-point mark.
Depleted Hornets struggle
Watford were without suspended trio Troy Deeney, Abdoulaye Doucoure and Marvin Zeegelaar.
And while manager Marco Silva said the enforced changes affected the performance, he also lamented the lack of quality from his players.
"There's been a lot of change in our starting XI so it's not easy," he told Match of the Day. "We are stronger with everybody available. We have three banned and five injured.
"I'm here to find the solutions. Even with injuries and bans we need to react and show different things. It's a moment for the other players to show their quality."
Andre Gray, who replaced captain Deeney, toiled as the lone striker and did not have a shot before he was substituted.
The Hornets had just one attempt on target, a weak Richarlison effort in the 56th minute.
Silva made three substitutions within seven second-half minutes but his team failed to spark into life.
Despite four defeats on the bounce, Watford are in 10th place, six points clear of the relegation zone.
"Now we need to react as a team and I hope we can have players available as soon as possible," added Silva.
Man of the match - Connor Goldson
Stats - Fortress Amex
- Brighton have lost just one of their past nine Premier League home games, winning three and drawing five.
- Watford have lost four consecutive Premier League games, as many defeats as they suffered in the previous 10 in the competition.
- The Hornets have now picked up just one point from their past six Premier League matches.
- The Seagulls scored a goal in open play for the first time in seven Premier League games - the last scored on 20 November.
- Gross has been directly involved in nine Premier League goals this season (four goals, five assists) - four more than any other Brighton player.
- Hemed has had a hand in four goals in his past five Premier League appearances at the Amex Stadium, scoring two and assisting two.
Brighton go to Chelsea on 26 December (15:00 GMT) while Watford host Leicester at the same time.
- 20MarchSubstituted forIzquierdoat 90+3'minutes
- 13GroßSubstituted forKayalat 83'minutes
- 10HemedSubstituted forMurrayat 87'minutes
- 23WatsonSubstituted forCapoueat 74'minutes
- 37PereyraSubstituted forSinclairat 71'minutes
- 18GraySubstituted forOkakaat 78'minutes
- Paul Tierney
- Shots on Target
Second Half ends, Brighton and Hove Albion 1, Watford 0.
Attempt missed. Stefano Okaka (Watford) right footed shot from the left side of the six yard box is close, but misses the top left corner.
Substitution, Brighton and Hove Albion. José Izquierdo replaces Solly March.
Offside, Brighton and Hove Albion. Davy Pröpper tries a through ball, but Glenn Murray is caught offside.
Solly March (Brighton and Hove Albion) wins a free kick in the defensive half.
Foul by André Carrillo (Watford).
Substitution, Brighton and Hove Albion. Glenn Murray replaces Tomer Hemed.
Attempt missed. Anthony Knockaert (Brighton and Hove Albion) right footed shot from the right side of the box is close, but misses to the right.
Attempt blocked. Tomer Hemed (Brighton and Hove Albion) right footed shot from outside the box is blocked. Assisted by Davy Pröpper.
Beram Kayal (Brighton and Hove Albion) wins a free kick in the defensive half.
Foul by Jerome Sinclair (Watford).
Substitution, Brighton and Hove Albion. Beram Kayal replaces Pascal Groß.
Offside, Brighton and Hove Albion. Solly March tries a through ball, but Pascal Groß is caught offside.
Attempt missed. Richarlison (Watford) header from the centre of the box is close, but misses to the right. Assisted by José Holebas with a cross.
Attempt blocked. Tom Cleverley (Watford) right footed shot from outside the box is blocked.
Attempt blocked. Stefano Okaka (Watford) right footed shot from outside the box is blocked.
Substitution, Watford. Stefano Okaka replaces Andre Gray.
Attempt missed. Christian Kabasele (Watford) header from the centre of the box is high and wide to the right. Assisted by Tom Cleverley with a cross following a set piece situation.
Foul by Solly March (Brighton and Hove Albion).