Arsenal missed the chance to close the gap to Premier League leaders Liverpool as they lost to West Ham.
Jarrod Bowen scored the winner on a nightmare afternoon for the Gunners at Emirates Stadium.
Arsenal knew victory would have moved them to within five points of Liverpool ahead of their trip to Manchester City on Sunday.
But, with Mikel Merino leading the line, Arsenal struggled all afternoon against a resolute West Ham side.
Bowen won it with his 50th Premier League goal when he stopped to head home a cross from Aaron Wan-Bissaka at the end of the first half.
Arsenal later had Myles Lewis-Skelly sent off when he was shown a straight red card for a professional foul on Mohammed Kudus near the halfway line.
This felt like a huge opportunity for Arsenal to put some pressure on Liverpool after Arne Slot’s side dropped more points against Aston Villa on Wednesday.
But defeat for Arsenal means Liverpool can move 11 points clear if they win at the Etihad.
West Ham held on comfortably in the end to move 13 points clear of the bottom three, as the Hammers secured only their second win under Graham Potter.
