West Ham were dumped out of the Europa League by Astra for a second season running, losing 2-1 on aggregate after a 1-0 reverse at London Stadium.
A late equaliser from Denis Alibec had restored parity in last week's first leg of the qualifying play-off, leaving Slaven Bilic's men with nervy memories of last year's exit at the hands of the Romanian minnows.
And the Premier League side were left to rue a host of missed opportunities in the return game as Filipe Teixeira's strike late in the first half settled the tie to prompt a chorus of boos from home supporters as West Ham fell at the final hurdle before the group stages.
While it had come from Astra's first serious attack, it was no more than the visitors deserved in an opening 45 minutes where they had hassled and harried West Ham.
The hosts saw chance after chance go begging in the second period, but could not force a crucial goal against a side that had shipped five in the league on Sunday, meaning Bilic has to pick up the pieces following a humbling way to exit the competition.
Bilic's star man Dimitri Payet was again missing, while Mark Noble also sat out, and his team made a slow start in their absence.
When a first chance did come in the ninth minute, Jonathan Calleri could not get the ball out from under his feet as he ran through, allowing Silviu Lung to smother.
The Astra goalkeeper had to be rather more impressive to beat away Pedro Obiang's low drive, but, despite a few nervy moments for the visitors, the home side continued to struggle.
And, on the stroke of half-time, Bilic's men fell behind.
A counter-attack arrived at Daniel Niculae's feet and he waited long enough for the support of Teixeira, who coolly tucked a finish under Darren Randolph to become the first opposition player to score at London Stadium in a competitive fixture since West Ham switched to their new home ahead of this season.
West Ham started the second half stronger, with Angelo Ogbonna nodding into Lung's hands before his team-mates squandered two marvellous opportunities.
As in the opening period, Calleri failed to connect properly from a great position, this time with his head, allowing Lung to parry, and Michail Antonio then stormed onto a powerful Sam Byram cross but directed over.
Cheikhou Kouyate volleyed wide before another headed chance arrived as Winston Reid angled an effort way off target.
It was starting to become apparent that West Ham's profligacy was going to cost them and Ashley Fletcher then surrendered the best chance yet, controlling Ogbonna's mishit to spring a fine stop from Lung with his close-range finish.
The outstanding Lung tipped Enner Valencia's free-kick away and likewise denied Fletcher from range as he clung on to a clean sheet and another incredible triumph.