West Ham produced a thrilling late comeback, twice coming from behind to stun leaders Chelsea 3-2 and leave the door wide open to their Premier League title rivals.
League leaders Chelsea travelled to the London Stadium knowing victory would extend their lead at the summit to four points before Manchester City and Liverpool even had the chance to kick a ball this weekend, but found a West Ham team who simply refused to be beaten.
Thiago Silva's towering header (28) had given Chelsea the lead Chelsea, but Manuel Lanzini hauled the Hammers level from the penalty spot (40) after Jorginho's poor back pass and Jarrod Bowen's tenacious press saw goalkeeper Edouard Mendy lunge in and concede the spot-kick.
Mason Mount restored Chelsea's lead with a sumptuous near-post volley (44) but the hosts roared back once again through Bowen's rasping drive (56), as Thomas Tuchel's side conceded more than one goal for only the third time in his 53-game tenure in charge of the Blues.
The hammer blow was administered in bizarre circumstances when Arthur Masuaku's fizzed cross (87) bamboozled Mendy, found the Chelsea net, and saw West Ham claim a first league victory in four to consolidate fourth place in the Premier League.
- Transfer Centre LIVE! Traore, Lingard, Alvarez latest
- 'Ngannou hits harder than Wilder - he'd KO Fury!'
- Fan arrested after Digne and Cash struck by bottle at Everton
- Aston Villa in talks with Juve over Bentancur
- Championship goals and highlights
- West Ham fans clash with police at Old Trafford after defeat
- Drone stops play at Brentford vs Wolves
- USA's No 1 heavyweight? 'Anderson will beat Wilder'
- Xhaka on red cards: This is who I am - I take risks
- Download Instructions
For Chelsea, a second defeat of the campaign ends an eight-game Premier League unbeaten run, leaves the door ajar to Manchester City and Liverpool and means the Blues could end the weekend as low as third.