Managerless Watford were relegated from the Premier League on the final day of the season as Pierre-Emerick Aubameyang inspired Arsenal to victory.
The Hornets, who dropped into the bottom three for the first time since 28 February in midweek, started the day level on points with 17th spot knowing a positive result could keep them up.
But they were 3-0 down after 33 minutes and, despite pulling back two goals, finish a terrible campaign 19th in the table following a 20th defeat.
Arsenal scored with their first three attempts on target, Aubameyang getting the first with a penalty after Craig Dawson's clumsy foul on Alexandre Lacazette inside the opening minute.
Scotland defender Kieran Tierney doubled the lead after Aubameyang's assist before the Gabon forward's classy overhead kick - his 22nd league goal of the season.
Watford pulled a goal back from the penalty spot through Troy Deeney after David Luiz's foul on former Gunners forward Danny Welbeck, who then made it 3-2 from close range.
Arsenal keeper Emiliano Martinez made a great save to deny Welbeck an equaliser that could have set up a dramatic finish.
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With Bournemouth beating Everton and Aston Villa drawing at West Ham, a point would not have been enough to save the Hornets because of their inferior goal difference.
Many of their players looked upset when Mike Dean signalled the end of the match - and Watford's place in England's top flight.
The Hornets are left to reflect on a chaotic season on and off the pitch which saw their Italian owners sack three managers over the course of the campaign, including Nigel Pearson a week ago.
Pearson was given his marching orders two games from the end of the season despite steering the team out of the relegation zone, with Hayden Mullins named interim head coach for the final week.
While Watford's previous two appointments, Javier Gracia and Enrique Sanchez Flores, managed one Premier League win in 14 matches between them, Pearson guided the Premier League's second-oldest squad to seven victories and 25 points in his 20 games in charge.
Watford had a six-point cushion over the bottom three after beating Newcastle on 11 July but head back to the second tier along with Bournemouth, who they were promoted with in 2014-15.
On Sunday, they needed to beat Arsenal and hope other results went their way but they got off to a terrible start when Dawson fouled Lacazette to gift their opponents a penalty which Aubameyang scored after a lengthy video assistant referee check.
Tierney made it 2-0 and Aubameyang's overhead kick after holding off Dawson added to Watford's misery before Deeney launched a spirited comeback.
Welbeck's clever backheel finish gave his side hope but they could not find an equaliser as they slipped to a sixth straight away defeat.
With the 2020-21 season starting on 12 September, the first task by Watford's owners will be to appoint a new head coach capable of inspiring a return to the top flight. Significant changes to the squad are also expected to be made.
More to follow.