For the second time in two matches Arsenal let a two-goal lead slip to damage their chances of becoming champions for the first time in 19 years.
Just as they did in the 2-2 draw at Liverpool last Sunday, Arsenal had the game in their hands only to drop two points.
Gabriel Jesus’ fourth goal in three matches, quickly followed by Martin Odegaard’s excellently-taken volley, put the Gunners two goals in front after only 10 minutes as they looked to be cruising to the three points at London Stadium.
But loose play from Thomas Partey led to West Ham collecting a penalty after Gabriel fouled Lucas Paqueta with Said Benrahma’s goal giving the hosts hope.
Bukayo Saka wasted a glorious chance to restore the two-goal advantage, firing wide from his own penalty, with Jarrod Bowen equalising two minutes later.
And it could’ve been even worse for Arsenal, who watched Michail Antonio head against the crossbar late on.
The title race is still in Arsenal’s hands and seven victories from their last seven games will see them win the league, although it’s now got that bit tougher as they will have to avoid defeat at Manchester City on 26 April to stop Pep Guardiola’s relentless side.