West Ham United's Development Squad suffered a 5-2 Barclays Under-21 Premier League defeat at Southampton, ending their hopes of a top-three Elite Group finish.
Though Elliot Lee and George Moncur had twice put the Hammers in the ascendency, the Saints fought back courtesy of Corby Moore and then Lloyd Isgrove to level at the break.
It looked to be delicately poised after the interval, until Sam Hoskins and Omar Rowe both struck in the space of three mad second-half minutes to turn the contest decisively in the Saints' favour. Jake Sinclair added a late fifth as an afternoon that had begun so brightly ended in bitter disappointment.
While it will come as little consolation, West Ham had earlier flown out the traps, with forward duo Lee and Sean Maguire continuing where they left off against Liverpool.
Reward for a fast start arrived after just four minutes, with a goal that owed as much to the patience and persistence of Maguire as it did the unerring finish of Lee.
Ben Marlow fed Lee, whose first-time flick allowed Maguire to bring the ball under his spell in the box, before picking his moment to slide into the path of his strike partner. The Hammers' No9 is in a rich vein of form just now and never looked like missing, bending it delicately into the far corner to notch his third in as many outings.
Rather than awakening the hosts, West Ham continued on the front foot and but for a brilliant stop, Lee would have been celebrating a second. Maguire, again, was the architect, whipping over a centre from the right-hand side. Lee's leap was timely and strong, but his header was clawed away by 'keeper Cody Cropper.
Eleven minutes in and there were more West Ham heads in hands. Moncur's deep corner picked out Marlow, whose header required the goal-line intervention of Moore.
Having prevented a goal at one end, Moore was soon responsible for the leveller at the other. Callum Chambers sped away down the right and despite the best efforts of Sebastian Lletget, was able to pick out Moore. The Saints forward finished every-bit as clinically as Lee before him, slotting a measured drive back across Baxter.
Far from surrendering the impetus, West Ham continued to plug away and took the lead for a second time in the 28th minute. Skipper Jack Stephens needlessly handled Pelly Ruddock's header, prompting referee David Woolford to point to the spot. Moncur stepped up and dispatched the spot-kick, sending 'keeper Cropper the wrong way.
It was a lead that would last until the stroke of half-time, before the scruffiest of goals squared things once more. Jake Sinclair burst into the box and his mishit shot was prodded home by the outstretched leg of Isgrove.
As the hour-mark approached, Hoskins had a gilt-edged chance to put the hosts in front, but headed Sinclair's pinpoint centre straight at Baxter.
It mattered not, however, as the Hammers' afternoon soon unravelled in the space of three forgettable minutes. Midway through the second period, miscommunication between Callum Driver and Baxter allowed Hoskins to nip in and fire the Saints into the lead for the first time.
And before the Hammers had time to catch breath it was four, when Rowe dispossessed Ruddock and drilled home. With less than five minutes to play, Rowe's corner was met by the seemingly unmarked Sinclair at the far post, who compounded the Hammers' misery with a fifth.
West Ham United: Baxter, Driver, Potts (Shaw 46), Ruddock, Spence, Bywater (McCallum 70), Marlow (Miles 46), Moncur, Lletget, Lee, Maguire.
Subs: Nemrava, Mavila
Southampton: Cropper, Chambers, Stephens, Turnbull, Targett, Curtis (Rowe 59), Reed, Moore (Gape 78), Sinclair, Hoskins, Isgrove (Seager 85)
Subs: Gazzaniga, Young