Declan Rice’s terrific first West Ham goal proved enough to give the Hammers a first league win over Arsenal since 2015, at the London Stadium.
The 19-year-old struck early in the second half, teed up by former Arsenal man Samir Nasri, as Unai Emery’s side put in a flat away performance.
Nasri was given the nod to face his old club from the start, while Marko Arnautovic was selected to lead the West Ham line, despite ongoing speculation about his future.
Mesut Ozil was left out of the Arsenal squad altogether as Unai Emery named the same XI that started the Gunners’ last Premier League game, the 4-1 win over Fulham.
Alexandre Lacazette looked sharp early on, sending a looping half volley wide and then forcing Lukasz Fabianski into a smart block.
It was the home side who had the better of a fairly drab half though, with Felipe Anderson coming closest with a low drive that whistled just past the far post, before Rice headed wide from a corner in the final minute of the first period.
It took just three minutes of the second half for Rice to make amends, as he curled into the top corner after Granit Xhaka had made a hash of clearing Anderson’s cross.
Arsenal brought on Aaron Ramsey and Lucas Torreira for Xhaka and Shkodran Mustafi, shifting to a back four in an attempt to find a way back into the game, and it was Ramsey’s clever flick that gave Alex Iwobi the chance to level but the Nigerian dragged his effort wide.
Arnautovic was replaced by Andy Carroll with twenty minutes to play, and appeared to wave goodbye to the home crowd as he left the field, ahead of a possible move to the Chinese Super League.
The defeat means Arsenal could end the weekend six points outside the top four, and could even slip to sixth if Manchester United hammer Tottenham on Sunday.