David Moyes rued poor decision-making after West Ham's faint hopes of scraping Champions League qualification were left hanging by a thread following a 1-1 draw at Brighton.
The Hammers were reliant on an 87th-minute equaliser from substitute Said Benrahma to salvage a point on the south coast, leaving them five points adrift of fourth-placed Chelsea with two games to go.
Moyes' men had the better of the chances at the Amex Stadium but fell behind during a frantic finale when Danny Welbeck claimed his 50th Premier League goal just six minutes from time.
The east London club have games against West Brom and Southampton to ensure the minimum of a Europa League place does not slip through their grasp, with Tottenham and Everton each just three points behind and in hot pursuit.
Hammers boss Moyes had no complaints about his side's display on Saturday evening but was less enamoured by their cutting edge.
"I thought we played very well for long periods of the game, especially first half," said Moyes.
"I thought Brighton improved in the second half, we didn't do enough in the final third. I thought our decision-making in the final third was poor.
"But overall I thought we played very well tonight. We didn't show enough quality in the pass, quite often it was the decision-making."
Algeria forward Benrahma drilled home his first West Ham goal from just outside the box to swiftly cancel out Welbeck's landmark strike and prevent his side slipping to a fourth defeat in five outings.
Hammers defender Craig Dawson had earlier squandered a golden chance to open the scoring with a free header, while Pablo Fornals wasted three presentable openings in the first half.
Moyes hopes Algeria forward Benrahma can kick on after ending a lengthy drought following his big-money from Sky Bet Championship club Brentford.
"We've been waiting for a goal and we got one tonight," said Moyes.
"We brought him in with that in mind and I am glad he has got that first goal and hopefully he will go on to get a lot more."
While West Ham were boosted by the return of influential England midfielder Declan Rice from a six-week injury absence, Brighton were forced into a reshuffle due to the suspension of key duo Lewis Dunk and Neal Maupay.
The lowly Seagulls remain in 17th place after being forced to settle for a league-high 14th draw of the campaign.
Despite conceding a late leveller, Seagulls boss Graham Potter had no objections to the result.
"I think it could have been a bit more because we were 1-0 up with not so long to go but I would say, over the course of the game, a draw is fair," he said.
"I don't think we can say we deserved necessarily to win. We were OK in the first half, we were better in the second.
"In the end it's a decent point against a team that's had a really good season and they were fighting for the points, so credit to the players.
"They gave everything again, restricted a good team to not too many chances and a nice goal from us."
