West Ham 0 Astra Giurgiu 1 (Astra win 2-1 on aggregate)
West Ham's European adventure was brought to an end before it had really begun - by a 35-year-old who used to play for Barnsley.
The Hammers crashed to their first defeat at the London Stadium, a humiliating 1-0 Europa League play-off loss to Astra Giurgiu, thanks to a goal from former Tykes and West Brom midfielder Filipe Teixeira.
It meant a 2-1 aggregate defeat to the team currently 11th in Romanian Liga 1, and no place in the group stage for Slaven Bilic's side - who would not even have had to play the play-off match had they beaten Stoke on the final day of last season.
Teixeira left England in 2010 on the back of an injury-hit couple of years in the midlands and Yorkshire, but returned to score the first competitive goal against the Hammers in their new home.
A desperately disappointing evening had begun on a high note with West Ham announcing the signing of young Swiss midfielder Edimilson Fernandes from FC Sion, but once again it was evident a striker is what they desperately need.
Manchester City's Wilfried Bony and Simone Zaza of Juventus remain targets but, in the meantime, rookie Argentine forward Jonathan Calleri was handed the responsibility in attack.
But the one-on-one Calleri missed in the dying seconds against Bournemouth on Sunday may have still been playing on his mind when Reece Burke played him through early on, the ball getting stuck under his feet allowing Astra keeper Silviu Lung to save
Pedro Obiang also saw a low 25-yard drive tipped around the post by Lung, but it was uninspiring stuff from the Hammers.
They paid the price on the stroke of half-time when Sam Byram's crossfield ball gave Burke too much to do and left both Hammers full-backs hopelessly out of position.
Astra defender Cristian Sapunaru beat Burke to the ball and it broke to Daniel Niculae, who played a simple square pass to Teixeira as he wandered through a huge gap in West Ham's defence.
With Byram desperately trying to make up the ground Teixeira was able to stride into the penalty area and slide the ball past Hammers goalkeeper Darren Randolph.
For the first time - and after just two-and-a-half competitive matches - boos rang around the former Olympic Stadium as the half-time whistle was blown.
West Ham went on the attack after the break but Lung performed heroics, keeping out headers from Angelo Ogbonna and Calleri while a diving Michail Antonio could not guide in Byram's vicious cross.
Sub Ashley Fletcher had a valid penalty claim waved away after he was bundled to the ground by Teixeira and was then denied by the leg of Lung from all of five yards out.
Lung palmed away Enner Valencia's free-kick and tipped Fletcher's shot wide, while Antonio did beat the visiting keeper after racing clear only for play to be hauled back for a foul.
The beleaguered Bilic resorted to playing centre-half James Collins in attack, but Astra survived five minutes of injury time as West Ham bowed out of Europe with a whimper.