Andy Carroll's 90th-minute equaliser edged Stoke City closer to Premier League relegation, cancelling out Peter Crouch's strike and earning West Ham a 1-1 home draw on Monday.
Crouch had been on the pitch nine minutes when he pounced to turn in the rebound after England goalkeeper Joe Hart spilled a shot from Xherdan Shaqiri.
But another substitute would yet have a decisive impact on the result, Carroll superbly turning in a cross from Aaron Cresswell to ensure the spoils were shared at London Stadium.
A run of four straight losses had seen Stoke's position appear increasingly perilous, the Potters in danger of slipping out of the Premier League after a 10-year top-flight stay.
Crouch had appeared to claim the role of hero with a goal that made him Stoke's record Premier League marksman, but Paul Lambert's men are on the brink after Carroll's leveller.
Stoke remain 19th in the table, five points adrift of safety with four matches remaining, one of which is against Champions League semi-finalists Liverpool at Anfield, while West Ham - who saw three goals ruled out - are seven clear of the drop zone.
Ramadan Sobhi and Moritz Bauer had early efforts saved easily by Hart as Stoke showed plenty of attacking ambition in the opening exchanges.
Marko Arnautovic was being booed by the visiting fans and the former Stoke man should have tested Jack Butland after being fed by Joao Mario, instead dragging his 32nd-minute strike wide.
Sobhi was proving Stoke's primary creative threat and he sent Mame Biram Diouf clear with a cute first-time pass around Declan Rice, but the Senegal striker fired straight at Hart.
With the tempo rising, Arnautovic hit the target with a powerful near-post drive only to find Butland in the way, the England goalkeeper in perfect position to block the effort with his face.
Arnautovic thought he had opened the scoring in the 55th minute when he glanced in Cresswell's cross, but the offside flag cut short his celebrations, replays showing the decision was marginally correct.
Diouf then missed Stoke's clearest chance, turning a Bauer pullback over the crossbar with a first-time strike that wasted a dangerous break.
Michael Oliver was refereeing a game for the first time since his controversial penalty award at the end of the Champions League quarter-final between Real Madrid and Juventus, a decision which led to abuse being directed towards his family on social media.
And the English official had to disallow another West Ham goal, Arnautovic in an offside position as he obstructed the view of Butland when the goalkeeper was beaten by Edimilson Fernandes' drive.
West Ham were building pressure on the Stoke goal and Butland parried away a Cresswell free-kick to protect his clean sheet, Lambert turning to Crouch in search of a key goal.
The former England international quickly came up with a massive moment for his side, showing attacking instinct to ram home the loose ball after Hart somehow let Shaqiri's strike slip out of his grasp.
44 - Peter Crouch has scored 44 goals for Stoke City in the Premier League, more than any other player (Jonathan Walters next on 43). Robot. — OptaJoe (@OptaJoe) April 16, 2018
West Ham's attacking pressure eventually told, though, Carroll showing poise and balance to volley a Cresswell cross beyond the reach of Butland to earn his side a point.
Oliver disallowed a third West Ham goal in added time, another substitute close to scoring a decisive strike, but Javier Hernandez's effort was ruled out for handball by Carroll in the build-up.
Key Opta stats:
- On home soil, West Ham have lost just one of their last seven top-flight games (W3 D3), after losing three of the six before that (W1 D2).
- Stoke are without a win on their last 19 Premier League visits to London, drawing seven and losing 12.
- This clash produced 36 fouls, a joint-high tally in the Premier League game this season (level with Chelsea v Manchester United on November 5).
- Peter Crouch is now on 16 sub goals in the Premier League (level with Javier Hernandez); only four players have more (Defoe 24, Giroud 19, Kanu 17 and Solskjaer 17).
- Andy Carroll has scored three goals in his last three Premier League appearances, spanning January (two games, two goals) and April (one game, one goal).