They had been profligate in the first-half, with Bryan Mbeumo a particular culprit, however the Frenchman atoned for his earlier misses soon after the break, latching onto a through-ball from Ivan Toney to power the Bees into the lead.
For the second goal, scorer turned provider and vice versa. Mbeumo met a cross at the back post and volleyed the ball across goal for Toney to head home and, in doing so, the striker sealed the three points as the visitors registered one of their more lacklustre performances of the campaign.
Story of the game
Brentford took to the pitch today hoping for a positive follow-up to what was arguably the greatest result in the club's history last weekend, when they defeated Chelsea 4-1 at Stamford Bridge in a simply stunning encounter.
And, sure enough, they started with the energy and enthusiasm characteristic of a team that is very much on a high, with three wins in their last four matches. The Bees pressed with a superb intensity right from the outset and did force their opponents into the odd mistake in their own half, however Lukasz Fabianski remained untroubled for now.
Chances were few and far between in the opening stages as both sides enjoyed lengthy spells of possession but struggled to break each other down. This game felt every bit like a Sunday afternoon.
The first real opportunity of the match came 20 minutes in when Ivan Toney dropped into midfield before playing a sublimely weighted pass behind the defence for strike partner Bryan Mbeumo to run onto. The Frenchman took the shot on first-time and stung the palms of Fabianski, who had to react very quickly indeed to make the save.
Moments later, West Ham ventured forward and they too worked a chance to score. Intricate build-up play saw Vladimir Coufal released down the right flank and the full-back whipped a cross right onto the penalty spot where Tomas Soucek was arriving, however the effort was right down the throat of David Raya between the sticks.
This encounter was beginning to open up. In a carbon copy of the earlier chance, Toney set Mbeumo in behind again and it looked as though the forward had all the time in the world to line up his shot, but Fabianski bore down on him to smother the effort. Good goalkeeping once more from the retired Polish international.
Brentford were certainly on top here, with midweek-related fatigue perhaps to blame for the amount of time and space West Ham were affording them in attack. Yoane Wissa surged down the left flank and put the ball across for Vitaly Janelt but, instead of shooting, the midfielder helped it on to Mbeumo, who ultimately took too long to get his shot away as the chance petered out.
Everything the Bees did well started with Mbeumo but, more often than not, ended with him, too. Just past the half-hour mark, Toney again showed superb vision to pick him out in acres of space on the right edge of the box, but the 22-year old blazed his effort high and wide of the target.
On the cusp of half-time, Brentford came within inches of taking the lead when Christian Eriksen's wicked delivery from a free-kick caused the visiting defence a whole world of problems. Coufal rose highest to head the ball but could only direct it towards his own goal and, with Fabianski caught off-guard, the Czech defender was relieved to see it clear the crossbar and drop on the roof of the net.
Merely a matter of moments after the restart, the hosts took the lead, and it came courtesy of the man who had been so profligate in the first period. Kristoffer Ajer's throw-in found Toney in the middle and the striker once more picked out Mbeumo, who this time made no mistake as he powered home at Fabianski's near post to score his first league goal since December.
On today's evidence, the understanding and connection between Brentford's front two is nothing short of telepathic. With an hour on the clock, Toney set his partner on crime through behind the defence again, but there was just too much on the pass and Fabianski rushed out to gather it.
Before long, however, the hosts' advantage was doubled, and those two were once again front and centre of the move. This time, Mbeumo was the provider as he met a whipped cross at the back post before volleying it back to the six-yard line where Toney was lurking to head it into an empty net.
Mbeumo was certainly central to this victory, but he showed his profligate side once again when he blazed a volley way over the target from ten yards after good work from Janelt down the left.
Not down and out just yet, West Ham created a good opportunity to peg a goal back when Declan Rice flicked on Said Benrahma's corner and Tomas Soucek very nearly made contact at the back post, but it just about evaded the midfielder's leap.
This was another impressive performance from Eriksen, and all he lacked was a goal or assist to show for it. He did enough to earn the latter when he set Toney through on goal with a beautifully disguised through-ball, however Craig Dawson won the ball with a robust but well-timed challenge, one that seemed to cause some pain to both parties, but which he certainly needed to make.
The final chance of the match fell the way of former Bee Benrahma, who wriggled free of Mathias Jensen's challenge and arced an effort towards goal from the edge of the box which dropped just clear of the crossbar.
Takeaways from the match
Toney and Mbeumo's partnership proves every bit as good as the chant that honours it
"I like it, here we go, Toney and Bryan Mbeumo!"
That was the soundtrack of this victory for Brentford, their fourth in five league matches as their Premier League status for next season is all but mathematically secured. Toney and Mbeumo have been pivotal in what has so far been a mightily impressive campaign for the Bees.
The former has been involved in 16 goals for the Bees this season, the latter 11, but today was their most impressive display as a pairing by some distance. They played with a telepathy which proved too much for the visiting back line.
The sheer amount of times the pair combined to wreak havoc among the West Ham defence and create openings for their own side was quite astounding. Perhaps the Hammers weren't at the races here, but few Premier League defences would've managed to keep Toney and Mbeumo out today — they were quite literally unstoppable.
Midweek fatigue shows for West Ham
They've been formidable all season, but West Ham were visibly off the pace here, and you couldn't be blamed for guessing that their midweek exertions had something to do with that — the 90 minutes against Lyon on Thursday (and 45 of those played with ten men) showed in their performance.
David Moyes' side didn't press effectively, left too many gaps at the back and passed up numerous opportunities to counter-attack for the simple fact that they didn't have the energy in their tanks. Nonetheless, they remained shrewd in possession and did work enough chances to score at least once. Ultimately, though, they can have no real complaints about the scoreline.
This has, unfortunately, been something of a recurring theme in the second half of West Ham's season — while they undoubtedly want to go as far in the Europa League as possible, the continuance of Thursday night fixtures could well come to jeopardise their chances of qualifying for next season's competition.
Brentford: Raya; Ajer (Roerslev 81'), Zanka, Pinnock, Henry; Eriksen, Norgaard, Janelt (Jensen 70'); Mbeumo (Canos 78'), Toney, Wissa.
Unused subs: Fernandez, Jeanvier, Bech, Baptiste, Fosu, Ghoddos.
West Ham United: Fabianski; Coufal, Dawson, Zouma (Diop 29'), Cresswell; Soucek, Rice; Bowen, Lanzini (Benrahma 58'), Fornals; Antonio (Vlasic 65').
Unused subs: Areola, Fredericks, Johnson, Masuaku, Kral, Yarmolenko.
Referee: Martin Atkinson
Following victory here, Brentford make the short journey to Hertfordshire next weekend to face relegation-threatened Watford at Vicarage Road.
West Ham, meanwhile, are back in Europa League action in midweek, travelling to Lyon for the tie's second leg in the hope of reaching the semi-final of the competition.