Mark Noble scored twice as West Ham thrashed 10-man Watford 4-1 at Vicarage Road to leapfrog their hosts and secure a top-half finish in the Premier League.
West Ham were two up against the run of play at the break, after captain Noble capped a fine individual effort by slotting home from the edge of the box on 15 minutes and Manuel Lanzini (38) reacted quickest to nod home after Ben Foster had tipped Michail Antonio's drive onto the bar.
But while the impressive Gerard Deulofeu (46) pounced on a Pablo Zabaleta error immediately after the restart to give Watford hope, Jose Holebas' straight red for tripping Antonio handed the advantage to West Ham - and also means he misses Saturday's FA Cup final with Manchester City.
Despite some brave initial resistance from Watford they were again slowest to the rebound when Marko Arnautovic (72) slid in his 10th of the season after Felipe Anderson had volleyed against a post. Noble then put the result beyond doubt when he coolly slotted in from the spot after Kiko Femenia had tumbled Antonio in the box to secure 10th place for West Ham and drop Watford to 11th.
Watford: Foster (7), Cathcart (7), Femenia (5), Holebas (4), Doucoure (6), Hughes (6), Kabasele (6), Capoue (6), Pereyra (6), Deulofeu (7), Deeney (6).
Subs: Mariappa (6), Masina (6), Gray (6)
West Ham: Fabianski (7), Balbuena (6), Diop (7), Lanzini (6), Fredericks (6), Antonio (7), Noble (8), Masuaku (6), Rice (7), Anderson (7), Arnautovic (7).
Subs: Wilshere (6), Zabaleta (5), Sanchez (6)
Man of the match: Mark Noble (West Ham)
How West Ham snatched 10th
Watford dominated much of the opening 45 minutes but were undone by wasteful finishing. They did have the ball in the net inside a minute when Deulofeu had been flagged offside and the attacker tested Lukasz Fabianski from 20 yards moments later.
Watford made two changes, with Etienne Capoue back from a groin injury and Christian Kabasele returning, too. Meanwhile, West Ham welcomed back Declan Rice and Felipe Anderson after illness.
Will Hughes then saw an overhead kick claimed by the keeper before Noble struck back for West Ham. The midfielder played a one-two around Etienne Capoue before surging forward and dropping a shoulder to wrong-foot Christian Kabasele and slot the ball into the bottom corner.
Roberto Pereyra then passed up two fine chances at the other end, tamely shooting at Fabianski before opting to try a pass when the strike looked on - and West Ham made Watford pay again. Lanzini was perfectly placed to head in from close range after Foster had brilliantly diverted Antonio's effort onto the underside of the woodwork.
Fabianski produced a sublime stop just before the break to keep out Troy Deeney but Watford pulled one back from West Ham's kick-off to the second half when Deulofeu raced onto Zabaleta's weak back-pass and rounded Fabianski before rolling the ball into the net.
However, hopes of a comeback took a hit just three minutes later when Holebas, who was making his 100th Premier League appearance, tangled legs with Antonio as he surged through at the other end and was shown a straight red which rules him out of Saturday's showpiece clash with champions City.
Watford showed resolve, though, and Deulofeu almost played Abdoulaye Doucoure through before the hosts saw three penalty appeals waved away, first when Antonio controlled the ball onto his arm in the West Ham box, then when Pereyra went down despite no contact from Fabian Balbuena, and finally when sub Andre Gray fell after turning Arthur Masuaku, who won the ball.
But eventually West Ham made their extra-man advantage tell and, shortly after Craig Cathcart had produced a stunning tackle to deny Arnautovic, the Austria forward tucked home a third from close range and Noble sent Foster the wrong way from 12 yards after Femenia lost possession and hauled down Antonio in the box.
Man of the match: Mark Noble
Captain fantastic was the key man in the middle of the park for West Ham on Sunday. He took his first goal brilliantly, sparking something out of nothing with a smart one-two and a clever dummy on the edge of the area before slotting in. his second from the spot was expertly dispatched, too. But, by then, the Hammers had taken control against their 10-man opposition - largely thanks to winning the midfield battle.
The managers' view
Javi Gracia, Watford: "We have another chance, a final to enjoy with our supporters. The final is the consequence of all the hard work we were doing before and we have to finish as well as possible.
"The season we've done was a good season, good work and now we have the chance, only one team out of the big six have, to play a final. We try to enjoy that moment. Because the season was the best ever in this club, we have to know it, give value and try to enjoy the final."
Manuel Pellegrini, West Ham: "To finish the first season in the upper part of the table is realistic, it is what this team is in this moment. We know we have six very strong teams and after that Everton, who over the last two or three years, have strengthened their squad so for the first season, to finish in the first 10 positions is not bad.
"I think we improved in points, in goals conceded, in goals scored. If you compare with the last season, when also we saw many troubles and problems inside the pitch, this season the fans enjoyed the games so I think we grow a step."
- Despite their defeat today, Watford recorded their highest season finish (11th) in the top-flight of English football since 1986-87 (9th place).
- West Ham won 15 games and picked up 52 points in the Premier League this season, both their most in a campaign since 2015-16 (16 wins, 62 points).
- Watford have not kept a clean sheet in any of their last 12 Premier League games - only once previously have they had a longer such streak in the competition (20 games between September 1999 and March 2000).
- West Ham have won consecutive away games in the Premier League for just the second time under manager Manuel Pellegrini, having previously won three in a row in December 2018.
- Since their return to the Premier League in 2015-16, Watford have picked up 16 red cards in the competitions, more than any other side.
- Only Paolo Di Canio (47) has scored more Premier League goals for West Ham United than Mark Noble (42).
- Gerard Deulofeu's goal for Watford (45:11) was the quickest at the start of the second half in the Premier League since January 2018 (also 45:11 - West Ham's Marko Arnautovic v Huddersfield).
- Manuel Lanzini scored his first Premier League goal for West Ham since the final day of the 2017-18 season (two goals v Everton on May 13, 2018).
Watford take on Manchester City in the FA Cup final on Saturday at Wembley, while West Ham head off on their holidays.