The London Stadium was far from full due to a boycott, but the fans in attendance were offered encouragement from the hosts’ intent in the opening minutes.
That wouldn’t last too long, though, as Brentford carried a threat of their own and Kevin Schade had hit the side netting before getting two headers off within 10 minutes.
Jarrod Bowen then fired wide from a tight angle before there was a break in play while Tomas Soucek received treatment for a head injury.
The hosts were pushed back after play resumed with Nathan Collins sending a header over and Dango Ouattara seeing his shot deflected behind before flicking Michael Kayode’s cross to Igor Thiago, who hit the crossbar.
Alphonse Areola then tipped Mikkel Damsgaard’s header wide and rushed out to smother Thiago, before Ouattara had one header diverted past the post by Bowen and sent another harmlessly wide.
Brentford finally got their opener in the 43rd minute, when a ball behind unlocked West Ham’s defence and Areola got a hand to Thiago’s shot but proved unable to stop it from trickling over the line.
The Brazilian appeared to have doubled his side’s lead seconds before the break, but he was caught marginally offside.
Nuno Espirito Santo responded by bringing on three defenders ahead of the restart, while Crysencio Summerville got them up the pitch but fired harmlessly off-target.
Soucek then saw his shot blocked by Sepp van den Berg, who squandered an opportunity at the other end by heading wide despite not being put under any pressure.
Schade then rattled the crossbar with his header, while Bowen was left furious after hitting his effort high and wide at the other end.
Areola denied Thiago and Keane Lewis-Potter’s strike curled narrowly wide, but after Konstantinos Mavropanos’ injury reduced the Hammers to 10 men, substitute Mathias Jensen finally found a Brentford second in the final moments as the Bees earned their first away points of the season.
They also left West Ham without a PL win at the London Stadium this campaign, as the Hammers have opened a top flight campaign with four consecutive home defeats for the first time ever.
Flashscore Man of the Match: Mikkel Damsgaard (Brentford)
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