Stewart Downing was back to his best as he scored a fine goal against Everton on Saturday. It was the sixth strike of an impressive season for the former Liverpool and Aston Villa midfielder.
But it was not enough to stop the Hammers falling to a last gasp defeat as Romelu Lukaku struck in injury time to complete a 2-1 turnaround.
The win saw Everton leapfrog the East Londoners into 10th place in the Premier League table.
But more significantly for the Hammers, it was the eighth time in all competitions they had conceded in the last five minutes of a game this season, and the fourth time they had shipped a crucial goal in stoppage time.
In total it has cost Sam Allardyce's side around 12 points and would see them challenging for a top six spot had they held their nerve better during the course of a campaign which had started so well.
The Irons had made their best start ever to a Premier League season with 31 points before Christmas putting them in the top four.
But just three wins from 20 league matches since means the season has ended in disappointment.
And in the wake of another defeat, Downing, 30, who has been reinvented as a central midfield playmaker this season, blamed 'mental weakness' for the decline.
“Maybe we’ve been getting a bit nervy in the last few minutes of games,” he told West Ham's official website.
“When you’ve been conceding late it could be on people’s minds, but you’ve got to block that out.
“In the first half of the season we were ruthless, but conceding late in games has cost us. With the points we’ve dropped we could have been in the top six."
Downing has been one of West Ham's better performers throughout the season and even earned an England recall.
His stats have been impressive and earlier this week he featured in a team compiled by website Football Republik based purely on the Fantasy Football points of English players in the Premier League alongside Liverpool's Jordan Henderson in the heart of the midfield.