The Hammers were a little unfortunate not to take anything from the match as they produced another good performance on the back of last Saturday’s victory against Southampton.
West Ham started very brightly and went close to scoring after only two minutes when Jarrod Bowen smashed a shot against the post.
When the Gunners responded Mesut Ozil’s shot was blocked by Aaron Cresswell but it was David Moyes’ side that enjoyed the better of the opening exchanges and Bernd Leno had to push Sebastien Haller’s shot away for a corner.
Arsenal went extremely close to breaking the deadlock midway through the first period only for Sokratis to head Pierre-Emerick Aubameyang’s cross against the bar.
West Ham continued to press and Leno had to keep out Pablo Fornals’ right-footed effort as Arsenal, who failed to have a shot on target in the first period, reached half time fortunate to still be level.
The Gunners were better at the start of the second period and Hammers goalkeeper Lukasz Fabianski did well to parry Eddie Nketiah’s left-footed shot. However, the visitors continued to create the better opportunities and Leno had to make a brilliant save to keep Michail Antonio’s header out.
Former Hull City striker Bowen forced Leno to make another stop while VAR ruled that Arsenal should not be handed a penalty when Lacazette went to ground under Angelo Ogbonna’s challenge.
With just 12 minutes remaining Arsenal grabbed the winner though when Lacazette lashed the ball home after Ozil had headed the ball to the Frenchman.
Haller went close to grabbing a late equaliser for the Hammers, who remain in grave danger of being relegated to the Championship after this defeat.