Mikel Arteta singled out Declan Rice's set-piece ability as the key to setting up an emphatic Arsenal win against the midfielder's boyhood club.
Rice provided two first-half set-piece assists for William Saliba and Gabriel which kickstarted the Gunners on their way, before scoring an impressive goal from outside the box.
Arteta said: 'I'm really happy with him (Rice). I know that it was an emotional day for him because he loves West Ham so much.
'But he had to focus on the task and what he had to deliver.