Second-half goals from Andre Gray and Isaac Success helped Watford bid farewell to the Sky Bet Championship with a 2-0 win over promotion hopefuls Swansea.
Chances were few and far between at Vicarage Road but Xisco Munoz watched his team put in an improved display after the break to conclude the regular season on another high.
Swansea will hope to join them in the Premier League and discovered they will face Barnsley in the play-offs, with the first leg set to take place on May 17 at Oakwell.
Watford made six changes from last weekend's defeat at Brentford and Ben Foster earned a recall for his first appearance since the previous meeting between the teams in January.
The former England man was the busier of the two goalkeepers during the early exchanges as first Andre Ayew tested him from a tight angle before he was forced into another fine save to deny Matt Grimes from 20 yards in the 19th minute.
Swansea were already guaranteed a play-off berth and somewhat surprisingly boss Steve Cooper played both Ayew and Chelsea loanee Marc Guehi from the off despite the duo only returning from hamstring and groin injuries this week.
With promotion secured last month and a much-changed XI selected, the hosts were disjointed in attack and after wasting a couple of promising situations, late in the half Philip Zinckernagel tried his luck from range but failed to hit the target.
A Ken Sema strike sliced wide for a throw summed up the quality on show at either end of the pitch during the opening 45 as it remained goalless at the break.
The deadlock should have been broken five minutes into the second period but Liam Cullen curled wide after a pass by Swans forward Jamal Lowe.
Lowe was involved again soon after with a dangerous dribble across the pitch before he set up Jay Fulton for a chance which was deflected over.
It would prove crucial as the opener finally did arrive in the 56th minute and it went to the hosts with their first shot on target.
Gray started and finished the move, with a wonderful pass via the outside of his boot to the left where Sema delivered a tantalising cross into the area that the Watford number 18 chested in for his fifth goal of the season.
Swansea defender Guehi had got a faint touch to the centre and it meant Gray knew little about the goal, but it capped a great week for the forward after fiancee Leigh-Anne Pinnock revealed on Tuesday she was pregnant with their first child.
Xisco introduced Will Hughes and Joao Pedro soon after while opposite number Cooper took off some of his key men like Ayew and Grimes with an eye on the play-offs.
Troy Deeney entered proceedings for goalscorer Gray with 18 minutes left in what could be both players' last appearances for Watford, with their respective futures uncertain.
Wayne Routledge nearly spoiled the Hornets' farewell to the second tier but his low drive was deflected wide by Christian Kabasele before the home side wrapped up the win with a second.
Freddie Woodman had produced a superb save to deny Achraf Lazaar minutes earlier but had no answer to Success, who smashed home on the half-volley in the 88th minute to add gloss to Watford's victory.
