West Ham stunned Arsenal to record a third successive Premier League victory, denting the Gunners’ title challenge in the process.
It was a ruthless display by West Ham, who converted two of their three shots on target, while Arsenal squandered a host of opportunities as they missed the chance to move top of the league.
Tomas Soucek fired in Jarrod Bowen’s cutback and, while the ball had potentially gone out of play in the build-up, there was not enough evidence for video assistant referee to overturn the goal.
That gave West Ham a first-half lead which was doubled when former Arsenal centre-back Konstantinos Mavropanos expertly headed in a corner in the 55th minute.
Despite plenty of possession and pressure, Arsenal could not find a response.
And their woeful night was nearly made worse when Declan Rice gave away a penalty in the final minute of injury time, but Said Benrahma’s effort was saved by David Raya.
The result leaves Mikel Arteta’s Gunners second in the table, two points behind league leaders Liverpool, while West Ham end the year with 33 points – their highest total at the halfway stage in a Premier League campaign.