West Ham suffered their first defeat in the Premier League at the Boleyn Ground since August as Swansea came away with a 4-1 victory.
Goals from Wayne Routledge, Andre Ayew, Ki Sung-Yueng and Bafetimbi Gomis made it a disappointing afternoon in the final ever Saturday game at the Boleyn.
The Hammers have enjoyed an impressive unbeaten home record in the top flight this season but that finally came to end as Swansea became the first side since Bournemouth back in August to come away with all three points.
Substitute Diafra Sakho pulled back a consolation goal for West Ham in the second half but it came too late to salvage anything from the game.
With the last ever home game at the Boleyn Ground against Manchester United on Tuesday night and the final fixture of the season against Stoke next Sunday, Slaven Bilic will still be hoping his side can get the victories they need to secure a European spot for next season.
The Hammers started the game strongly and dominated the opening 20 minutes.
They could have opened the scoring after just two minutes when Dimitri Payet weaved his way to the edge of the box and curled a low shot which was well saved by Lukasz Fabianski diving low to his left.
From the resulting corner Winston Reid rose the highest inside the box and saw his downward header produce another fine save from the Swansea keeper.
The home side came close again on ten minutes when Andy Carroll cut the ball back for Mark Noble who was unmarked on the edge of the box but fired his shot over the bar.
After winning five awards at the end of the season ceremony this week, Payet was full of confidence going into the game and would have fancied his chances when the Hammers were awarded a free-kick on the edge of the box.
But the Frenchman curled the set-piece inches over the bar.
The Hammers were made to pay for those missed opportunities as Swansea opened the scoring on 25 minutes.
Ki Sung-Yeung played the ball out to Kyle Naughton who crossed in first time for the unmarked Routledge who made no mistake striking the ball into the back of the net.
The Hammers could have drawn level straight away when Fabianski failed to deal with a corner on 29 minutes and the ball fell to Victor Ogbonna who had the goal at his mercy but he fired his shot over the bar.
But it was Swansea who doubled their lead on the half hour mark. Stephen Kingsley burst clear down the left hand side and played the perfect cross in for Ayew who was free inside the box and struck the ball home from close-range.
It could have been a different story if the Hammers had managed to pull a goal back right on the stroke of half-time.
Michail Antonio whipped the cross in which Carroll did well to divert the ball back across goal and Manuel Lanzini saw his shot go just over the bar.
Swansea made it three on 51 minutes when Modou Barrow crossed the ball in from the right hand side and Sung-Yueng produced a great piece of skill to volley the ball past Randolph into the corner of the net.
West Ham refused to lie down and could have pulled one back on 53 minutes when Antonio saw his close-range shot produce a great reflex save from Fabianski. The ball fell to Carroll and he fired his shot inches past the post.
The Hammers finally found a breakthrough on 68 minutes when Payet's cross picked out Sakho who saw his first shot well saved by Fabianski, but he made no mistake with his second attempt as he diverted the ball into the corner of the net.
But it was only a consolation as Swansea wrapped up a comfortable victory with their fourth of the game in injury time after Gomis played a neat interchange with Ayew and struck the ball into the back of the net.
The Hammers will be hoping for a much better outcome when they play the final ever game at the Boleyn Ground against Manchester United on Tuesday night.
West Ham: Randolph, Antonio, Cresswell, Reid, Ogbonna, Noble, Kouyate (Emenike 76), Moses (Sakho 59), Lanzini (Valencia 83), Payet, Carroll
Subs not used: Spiegel, Tomkins, Obiang, Collins
Bookings: Sakho, Reid
Swansea: Fabianski, Naughton, Kingsley, Fernandez, Amat, Ki, Fer, Cork, Routledge (Gomis 81), Barrow (Rangel 69), Ayew
Subs not used: Nordfeldt, Emnes, Britton, Gorre, Fulto
Referee: Michael Oliver