Hammers substitute Diafra Sakho was on target but it was mere consolation as they were swept aside by the Swans

West Ham United 1 Swansea City 4

The last-ever 3pm kick-off on a Saturday afternoon at a sold-out Boleyn Ground definitely did not go to plan as Swansea gatecrashed the party to end the Hammers’ ten-game unbeaten Premier League run and send the disappointed claret and blue supporters home with a huge hangover.

First-half goals by Wayne Routledge and Andre Ayew had already dampened East End spirits, before Ki Sung-Yueng trebled the lead just after the break and, although Diafra Sakho scrambled one back, substitute Bafetimbi Gomis all but ended West Ham’s slim chances of Champions League qualification with a stoppage-time fourth.

Following last Saturday’s three-goal walloping of West Bromwich Albion, Slaven Bili? made two changes as Darren Randolph replaced the injured Adrian (calf) between the posts, while Victor Moses came in for substitute Sakho.

The Swans, kicking-off seven places and 16 points adrift of the Hammers - but safe from the drop - made half-a-dozen switches from the side that beat Liverpool 3-1 last Sunday, as Francesco Guidolin unselfishly rested Ashley Williams ahead of Euro 2016, while Jefferson Montero, Gylfi Sigurdsson, Neil Taylor plus substitutes Angel Rangel and ex-Hammers starlet Leon Britton missed out, too.

That saw call-ups for Sung-Yueng, Leroy Fer, Kyle Naughton, Federico Fernandez, Stephen Kingsley and Modou Barrow, who each walked out to rousing rendition of ‘I’m Forever Blowing Bubbles’ before soon seeing Hammer-of-the-Year Dimitri Payet force Lukasz Fabianski to tip his low, curling 20-yarder around his left-hand post.

Then from the consequent corner, Winston Reid’s header was again saved at full-length by the Swans’ keeper, before the Kiwi saw another tightly-angled shot deflected behind and then Mark Noble got in on the act, too, dispatching a rising 20-yarder high into the Sir Trevor Brooking Stand.

It was all West Ham United and, on 17 minutes, Jack Cork’s handball 25 yards out, saw Payet curl a dipping free-kick just a whisker over the crossbar, before a Fernandez foul on Cheikhou Kouyate allowed the Frenchman to whip another award just inches past the left-post.

A goal was certainly on the cards but it was the fact that it went to Swansea that caused consternation in the East End as Man-of-the-Match Sung-Yueng burst down the left and crossed deep to Naughton, who sent a first-time cutback to the edge of the six-yard box, where Routledge gave the visitors a 24th-minute lead with his second goal of the campaign.

Angelo Ogbonna should have replied instantly, but he wastefully skewed a half-cleared corner high over and, back in his own half, the Italian could only look on in horror as Ayew got in front of him to side-foot home Kingsley’s left-wing centre and double the Welsh lead on the hour-mark with his 11th strike of the season.

By now, the Boleyn Ground party was turning into a wake, Sir Trevor and Lady Brooking were looking on stony-faced and the breaking Barrow could have made it yet worse but his right-footer ripped into the boards to relief all around as the Hammers - who saw Manuel Lanzini slide over with the last kick of the half - restricted the deficit to just two at the break.

That respite did not last long, though, for on 51 minutes, Barrow left Michail Antonio looking at the soles of his blistering boots as he scorched down the left flank and crossed into the area, where Sung-Yueng blasted the ball past Aaron Cresswell to double his goals tally for the season.

At the other end, Antonio had a point-blank effort blocked by Fabianski, before Sakho replaced the ineffective Moses for the final half-hour and the substitute responded to the call by reducing the deficit midway through the half.

On 67 minutes, Payet crossed from the left and, although Fabianski smothered Antonio’s downward header and then blocked Sakho’s follow-up, the Senegalese striker finally bundled home his seventh goal of the season at the third attempt to give West Ham the tiniest glimmer of hope.

Sakho was then booked for an aerial challenge on Swansea substitute Rangel, before Emmanuel Emenike and Enner Valencia stepped from the bench as Kouyate and Lanzini retired but the clock was simply ticking down too quickly on West Ham, who faced further misery in added time, when the breaking Swans glided upfield and, with only Noble to protect poor Randolph, Ayew invited supporting substitute Gomis to tap home their fourth.

This was no way to draw down the curtain on a Saturday afternoon in E13 and, although the heartbroken Hammers fans were certainly not singing their way back down Green Street, the fat lady could, at least, be heard warbling ahead of Tuesday night’s finale against Manchester United.

HAMMERS: Randolph, Antonio, Cresswell, Reid, Ogbonna, Kouyate (Emenike 77), Noble, Moses (Sakho 59), Lanzini (Valencia 83), Payet, Carroll. Unused subs: Spiegel, Tomkins, Obiang, Collins.

SWANS: Fabianski, Amat, Kingsley, Naughton, Fernandez, Fer, Cork, Sung-Yueng, Routledge (Gomis 82), Barrow (Rangel 70), Ayew (Britton 90+3), Unused subs: Nordfeldt, Emnes, Gorre, Fulton.

Booked: Sakho (59), Reid (81), Ogbonna (85).

Referee: Michael Oliver

Attendance: 34,907