Despite falling behind twice in today's Premier League match against Chelsea, David Moyes' West Ham United stunned the Blues by taking all three points just minutes before the final whistle.
The Hammers had to come from behind twice, with Manuel Lanzini canceling out Thiago Silva's header and Jarrod Bowen restoring parity following Mason Mount's magnificent volley.
However, just as the London Stadium appeared to be heading for a draw, Masuaku's cross beat Mendy at his near post and flew into the top corner, handing David Moyes' side a memorable victory.
Both sides posed a threat in the opening stages, but Chelsea took the lead.
Thiago Silva headed in from a Mount corner, and despite Lukasz Fabianski's best efforts, the goalkeeper was powerless to stop it. Silva was on hand a minute later at the other end of the pitch, brilliantly clearing a Coufal shot off the line to deny West Ham.
The Hammers were then gifted a way back into the game by Edouard Mendy. Jorginho's backpass was poor, and Mendy took too long to recover the ball before losing it and then bringing down Bowen. Lanzini converted from the spot to bring his side level.
However, Chelsea led at the break. Mount cushioned a sublime volley past Fabianski at the near post after Hakim Ziyech floated a crossfield switch to him. Bowen then equalized for the Hammers ten minutes into the second half. Vladimir Coufal pushed the ball inside, and Bowen curled the ball into the far corner.
With 15 minutes remaining, the hosts came dangerously close to taking the lead. Antonio slid in and played a ball across the face of goal, but Bowen was unable to divert it into the empty net from a few yards out.
However, West Ham scored the game-winning goal with just three minutes remaining. Masuaku's left-footed cross into the box beat a scrambling Mendy at his near post, much to the delight of a raucous London Stadium crowd.
As a result, West Ham will finish the weekend in the top four, while Chelsea may lose their lead at the top, depending on how Man City and Liverpool fair in their matches.