Gareth McAuley's header deep into stoppage time earned West Bromwich Albion a 2-2 draw in a lively mid-table Premier League scrap at the London Stadium on Saturday.
Manuel Lanzini's swerving shot in the 87th minute looked to have sealed a comeback victory for West Ham but McAuley denied them, although the goal was initially credited to Jonny Evans.
West Brom took an early lead when Nacer Chadli punished slack home defending to fire home and Salomon Rondon struck the woodwork as the visitors bossed the opening stages.
But West Ham improved and Sofiane Feghouli equalised just past the hour, tapping in after Manuel Lanzini's curling shot was tipped against the crossbar by West Brom keeper Ben Foster.
West Ham went ahead when Argentine Lanzini was rewarded for an impressive display by firing home a fiercely-struck shot after a fine pass from Feghouli.
West Brom had the last laugh, though, when Evans and McAuley both attacked Chris Brunt's swirling corner but McAuley got the decisive contact to deny West Ham only a sixth home league win out of 13 at their new stadium.
"The players have played some smashing stuff at times. They kept fighting and fighting and never gave up. We have 13 games to go and we still need to try and get as many points as we can," West Brom manager Tony Pulis said.
The frustration was too much for West Ham manager Slaven Bilic who was sent to the stands after taking out his anger on a pitch-side TV microphone.
West Ham are 10th with 32 points while West Brom are eighth on 37.
(Reporting by Martyn Herman, editing by Ed Osmond)