Ten-man West Ham fell short of reaching a first major European final for 46 years as they were beaten 1-0 at Eintracht Frankfurt in Thursday's Europa League semi-final second leg, losing the tie 3-1 on aggregate.
Aaron Cresswell was sent off after 19 minutes following VAR intervention for denying a goalscoring opportunity, before an unmarked Rafael Santos Borre opened the scoring from close range (26) to extend Frankfurt's aggregate lead.
West Ham manager David Moyes was also sent off after he angrily kicked a ball towards a ball boy in the 78th minute, having watched his side struggle to recover after going a man down.
Explaining his dismissal, Moyes said: "I have to apologise for kicking the ball but the ball boy left it short and it was nicely on the volley for me."
Frankfurt, who remain unbeaten in the Europa League, will play Rangers - who beat RB Leipzig 3-2 on aggregate - in the final on May 18 in Seville.
The final whistle cued scenes of jubilation as thousands of Frankfurt fans poured onto the pitch and police had to get involved to ensure the situation remained peaceful.
West Ham's European journey comes to a frustrating end
Frankfurt's colossal defender Martin Hinteregger was forced off inside seven minutes after sustaining a suspected hamstring injury, with Almamy Toure coming on in his place.
His departure left Frankfurt looking nervy until Cresswell's sending off.
The West Ham defender, who was shown red against Lyon in the quarter-final stage, was caught out by a long ball over the top to Jens Petter Hauge.
Unable to track the flight of the ball, an isolated Cresswell grabbed hold of the Frankfurt forward before pulling him down with none of his West Ham team-mates around to cover.
The referee initially awarded a yellow card, but was sent to his monitor by VAR and rightly decided to send Cresswell off for preventing a goalscoring opportunity.
Just seven minutes later, Frankfurt made their numerical advantage count as Ansgar Knauff, a goalscorer in the first leg, turned provider for Borre with a neat cut-back, which found the striker totally unmarked on the edge of the six-yard box and he finished with ease.
West Ham, who lost their way after the sending off, came agonisingly close to equalising on the night a minute before the break as Kurt Zouma's chested effort - after Jarrod Bowen's free-kick - was cleared off the line by defender Evan N'Dicka, a reported target for Manchester United and Newcastle.
The Premier League side threw everything they could at Frankfurt in the second half, but they failed to produce any cutting edge in the final third, and eventually grew weary.
Frustration spilled over in the closing stages as Moyes was sent off after kicking a ball at a ball boy after feeling the ball took to long to come back to him. His actions sparked scenes of fury from the Frankfurt bench, and he was given his marching orders, leaving the pitch without protest.
There was a late chance for West Ham in the 90th minute as Soucek was picked out at the back post from a set-piece only for the midfielder to head wide on a deeply frustrating night for the Hammers.
'Gutted' Rice fuming with referee
West Ham midfielder Declan Rice was angry about the officiating by Jesus Gil Manzano and felt the referee's decisions favoured Frankfurt - but accepted the Cresswell red card was fair.
Rice, who appeared to be booked for something he said to the ref, told BT Sport: "The red card was the right decision looking back at it. But none of the decisions seemed to go for us.
"The ref seemed to make every decision go for them and when you've got someone against you, you can't do much."
Despite his clear frustration and anger, Rice was pleased with the performance of his side and promised they would be back.
"We are gutted, we've come so far as a group," added Rice. "We've given everything this year, you know we are not the biggest of squads and to keep playing week in week out, over 50 games a season after last year.
"I'm proud as well. To go down to 10 men and to put in that shift, many teams would go away and lose by three or four. The way we tried to defend and get forward with a man less emphasises everything that West Ham is about.
"We will fight until the end."
Moyes: We've enjoyed EL, but not the officiating
David Moyes also felt aggrieved about the referee's performance, saying "we've enjoyed being in the competition, I don't know if we've enjoyed the officiating".
Asked if he had complaints about the red card, Moyes told BT Sport: "I have lots of complaints, yeah."
Asked about his sending off, Moyes said: "I kicked a ball back at the ball boy so I apologise for that, but he threw it very softly at me."
He added: "Really disappointed. Things didn't go for us on the night. Small things didn't happen but I am really proud of the players. How they played with 10 men was fantastic. They stayed in it. Other teams would have folded and lost two or three. The boys here are great. Tough boys.
"I thought we tried. We created chances. I thought we had better chances than Frankfurt. But we congratulate them. They go through, we don't and we give them our best wishes.
"I don't feel any of that [pride] at the moment. I just feel disappointment as I felt this was a chance. We have played better teams probably than Frankfurt. Let's be honest, we probably lost the game in the first 30 seconds at the London Stadium when we conceded. We were chasing the game since.
"We have enjoyed being in the competition. Not sure we have enjoyed the officiating. We have a pretty good team so I think we can try again. We will be a bit wiser and can hopefully do it more often."
West Ham's fixture schedule
Sunday - Norwich (a) Premier League
May 15 - Manchester City (h) Premier League, live on Sky Sports
May 22 - Brighton (a) Premier League
What's next for West Ham?
West Ham travel to relegated Norwich on Sunday as they look to reignite their push for a top-six finish in the Premier League after four games without a win domestically, losing three of those. The Hammers play host to league leaders Manchester City the following Sunday, live on Sky Sports, as the visitors chase a third consecutive title.