With the second leg of West Ham’s Europa Conference League semi-final against AZ Alkmaar in mind, David Moyes made nine changes to his side.
Yet it was a sparingly-used Brentford player that had the game’s first opportunity, as Mikkel Damsgaard glanced his header wide from Kevin Schade’s cross on the Dane’s eighth league start of the campaign.
The Bees then sprung into action to punish Nayef Aguerd's sloppy pass after a slow 20 minutes, as Mathias Jensen slid the ball through for Bryan Mbeumo to beat Lukasz Fabianski.
The Hammers did very little to make things difficult for their hosts, who cut through them with ease to set up an opportunity for Yoane Wissa, although his powerful strike was well dealt with by Fabianski.
More chances arrived and a long throw from Jensen caused absolute havoc in West Ham’s box, as Schade, Wissa, Damsgaard and Ben Mee all saw their attempts blocked.
The visitors didn’t get any better at dealing with that aerial threat, as another Jensen throw was flicked on by Mee for Wissa to head home to double their lead.
Danny Ings had a rare opportunity moments later but was halted by a strong hand from David Raya, and West Ham were sloppy again after the break, with Tomas Soucek being let off when he lost possession on the edge of the box as Wissa fired wide.
Moyes responded with a triple change as the hour mark approached and Said Benrahma floated across a ball that came off the post and was pulled back by Manuel Lanzini for Ings to head in.
However, Hammers' hopes were quashed as Divin Mubama was adjudged to have handled the ball after it struck the woodwork.
So, even with Fabianski impressively stopping Mbeumo’s late header, Brentford comfortably saw out the third win from their last four matches to go ninth in the table.
They also ended West Ham’s run of back-to-back wins across all competitions, although the Hammers will be more concerned about ensuring they get past AZ Alkmaar to reach their first European final since 1976.
Flashscore Man of the Match: Mathias Jensen (Brentford)
