Diafra Sakho broke Swansea City hearts with a late winner to hand West Ham a perhaps unwarranted 1-0 victory.
Paul Clement's charges had seemed on course to prevent the home side from scoring for the first time in 32 encounters but the Senegal striker's 90th-minute strike ensured all three points stayed in west London.
The defeat for the Swans means the south Welsh club conceded for the first time on the road this term and still only boast one Premier League victory in 2017/18.
Michail Antonio, a surprise inclusion after he trudged off last Saturday with a groin strain, drew a fine stop from Lukasz Fabianski with a bouncing volley from Aaron Cresswell's teasing centre.
Good link-up play between the Hammers' front two then saw Andy Carroll force Fabianski into a routine save, while Joe Hart's leaping save denied Wilfried Bony's fierce effort finding the back of the net.
Pablo Zabaleta's timely block prevented Tom Carroll firing goalward after a flowing Swansea move - the away side's diamond formation completely dominating the midfield areas with West Ham struggling to assert themselves.
Andre Ayew's flicked header was comfortably held by Fabianski as the home outfit tried to impact proceedings, and the watching crowd were relieved to hear the half-time whistle after a low-key first 45.
Carroll continued to cut a despairing figure as yet another West Ham free kick wasn't whipped into his towering frame soon after the restart, but the striker only had himself to blame as he agonisingly failed to connect with Antonio's super ball from the right wing.
Fabianski bravely challenged Carroll for a high ball pumped into the box and came off worse in the resulting collision as both clubs threw on playmakers Manuel Lanzini and Roque Mesa in a bid to inject some creativity onto the pitch.
Martin Olsson was inches away from infuriating the West Ham faithful further as the full-back's right foot shot just curled the wrong side of the post before Carroll squandered the best chance of the game.
Arthur Masuaku's low cross was sidefooted goalwards by the forward, but his effort cannoned back off the angle of post and crossbar five minutes from time.
And, just shy of the 90th minute mark, West Ham snatched the win. Masuaku drove down the left flank, arced a low centre across the face of goal and Sakho slammed home at the back stick to the relief of their home crowd.