West Ham boss David Moyes said his side lost their Europa League semi-final tie with Eintracht Frankfurt in the first minute of the first leg last week.
Defender Aaron Cresswell and Moyes himself were both sent off in Germany.
"Let's be honest, we probably lost the game in the first few seconds at London Stadium when we conceded," Moyes said.
"We were chasing the game since."
Frankfurt will now face Rangers in the final, while West Ham's wait for a trophy goes on to a 43rd year. They are currently seventh in the Premier League, which would be a Europa Conference League spot.