London - Winston Reid's unfortunate own goal prevented West Ham United from claiming a first win in four Premier League games as they drew 1-1 with West Bromwich Albion on Sunday.
In the 100th meeting between the teams, Mauro Zarate put West Ham ahead in the 17th minute at Upton Park with a fine free-kick that curled into the top-left corner.
But West Brom drew level five minutes after half-time when substitute Rickie Lambert's snapshot took a cruel deflection off New Zealand defender Reid's arm that sent the ball spinning into the net.
Slaven Bilic's West Ham, who last won against Chelsea in late October, climbed one place to seventh in the table, while West Brom remain 13th.
West Brom manager Tony Pulis made just one change, Gareth McAuley replacing the suspended Chris Brunt, and the visitors threatened first, with Salomon Rondon shooting narrowly wide in the 13th minute.
But four minutes later West Ham went ahead after McAuley's foul on Diafra Sakho presented Zarate with an opportunity to take aim from 25 yards.
The Argentine forward did not spurn the invitation, shaping a glorious shot right into the top-left corner for his fifth goal of the season.
The goal energised Bilic's men and they twice went close before half-time.
Cheikhou Kouyate could only head wide from Aaron Cresswell's cross, while Manuel Lanzini stung West Brom goalkeeper Boaz Myhill's palms with a first-time shot after a jinking run and pass from Zarate.
Pulis introduced Lambert for Stephane Sessegnon at the interval and the former Southampton and Liverpool striker made an immediate impact.
After Darren Fletcher won possession on the edge of the West Ham box, Lambert took aim with a left-foot shot that cannoned off Reid's arm and left goalkeeper Adrian wrong-footed.
Now it was the visitors who were on top, with Adrian parrying Lambert's low free-kick and then producing a starfish save to repel Rondon's close-range header from Fletcher's cross.
Bilic sent on Andy Carroll for Pedro Obiang, only to then see another of his strikers, Sakho, hobble off after hurting himself as he took aim at goal in the 72nd minute.
West Ham came closest to snatching the points in the closing stages, but Victor Moses's left-foot volley flashed the wrong side of the post and Cresswell's stoppage-time free-kick was turned away by Adrian.