Leandro Trossard lashed home from Martin Odegaard’s pass to give the visitors a crucial lead late in the match.
Sub Callum Wilson fired in after David Raya’s punch in added time, but after a long VAR check it was ruled out for a foul on Raya by Pablo.
Raya had also made a stunning late stop to deny Mateus Fernandes after the midfielder had burst through one-on-one.
Here’s how the top of the Premier League standings look after that priceless win for Arsenal.
They are five points clear of Manchester City, who have a game in hand. Even if City win that, Arsenal have a two-point gap.
Here are the numbers at the end of all that. West Ham had their chances come the end and arguably had a claim they deserved a point.
