Said Benrahma came off the bench to net the only goal as Brentford exited the Emirates FA Cup at the hands of West Ham United.
A match of little goalmouth action was decided by a moment of brilliance from the former Bees favourite with 11 minutes to play; his 20-yard effort arching in over Thomas Strakosha.
New signing Kevin Schade made his debut as a substitute but he couldn’t inspire a comeback as Brentford suffered a first defeat since November in all competitions.
Seven changes for Brentford with new man Schade among the substitutes
Thomas Frank made seven changes from Monday’s victory over Liverpool; Mads Roerslev, Ben Mee, Mathias Jensen and Yoane Wissa were the players to retain their spots.
Strakosha came in for his first appearance since August while Wednesday’s arrival Schade was named among the substitutes.
West Ham made four changes from their draw with Leeds United on Wednesday night: Ben Johnson, Michail Antonio, Angelo Ogbonna and Emerson came into the starting XI
Brentford: Strakosha; Roerslev, Ajer (Henry 80), Mee (Trevitt 90), Bech, Ghoddos; Jensen, Dasilva (Janelt 68), Damsgaard (Canos 80); Wissa, Lewis-Potter (Schade 68)
Subs not used: Cox, Zanka, Stevens, Yarmoliuk
West Ham United: Fabianski; Ogbonna, Dawson (Booked 73), Aguerd; Johnson, Rice, Soucek (Benrahma 68), Paquetta (Downes 87), Emerson; Bowen, Antonio (Fornals 87)
Subs not used: Randolph, Cresswell, Kehrer, Coventry, Swyer, Mubama
Attendance: 16,725
Wissa comes closest during a first half of few chances
The two sides, both in 5-3-2 systems, cancelled each other out during the opening 45 minutes.
The possession that both sides saw was all in areas unlikely to hurt the opposition and both defences were happy with that.
Brentford did look slightly the more threatening and had the evening’s first opening. The front two of Keane Lewis-Potter and Wissa combined with the former finding the latter eight yards out. However, Lukasz Fabianski spread himself well to turn Wissa’s low close-range shot behind.
A Lewis-Potter header was blocked by Nayef Aguerd, VAR taking a quick check to confirm that a hand wasn’t involved, before West Ham had their first sights of goal.
None of them came to much with Antonio’s tame long-range effort blocked and Lucas Paquetta sending the loose ball high into the west stand.
Jarrod Bowen then let fly from 30 yards but the ball skuttled well wide.
Good defensive work from Mads Roerslev won the ball back high on the West Ham left. Mikkel Damsgaard and Lewis-Potter then combined for the former Hull man to shoot over from 25 yards.
The final real action of the half saw Ben Mee strike the post from close range, although the flag subsequently went up for offside against Lewis-Potter in the build-up.
Substitute Benrahma delivers decisive blow
The opening exchanges of the second half hinted at a more open affair, with both sides looking far more dangerous.
For the first real time on the evening, Brentford got some space to drive into with Wissa playing in Lewis-Potter down the left – his cross easily gathered by Fabianski.
West Ham really should have been ahead moments later but somehow Bowen hooked Emerson’s centre across goal and wide from eight yards with only Strakosha to beat.
Ogbonna and Roerslev made a pair of blocks to deny Damsgaard and Emerson but the game slipped back into a lull after that bright opening to the second period.
Lewis-Potter’s looping header across goal, and a Mads Bech block on Declan Rice, were the only real moments of action until both sides called for reinforcements.
Schade came on for his Brentford debut while former Bee Benrahma was one of those called off the West Ham bench.
Schade had a number of bright moments in his cameo, but it was Benrahma who would provide the evening’s crowning act with 11 minutes to play.
Rice crunched into a tackle on Wissa in the centre circle, with Benrahma picking up the loose ball. The Algerian drove to the edge of the box before unleashing a fierce, swerving effort which left Strakosha rooted to the spot as it flew in.
Brentford pressed for an equaliser but couldn’t fashion anything more than half chances.
Sergi Canos’ effort from the edge of the box was deflected over by Ogbonna, Vitaly Janelt blazed over from range and Schade had a shot blocked by Aguerd.
The final effort of the night dropped for Wissa but there would be no more late heroics from the Bees frontman as he shot wide signalling Brentford’s exit from this year’s competition.
Frank: We didn’t have that final, quality decisiveness
Thomas Frank focused on the positives following Brentford’s FA Cup exit.
Ajer: It's great to be back
Defender Kristoffer Ajer praised the club's medical team for helping him get back to full fitness, after he featured in Brentford's FA Cup defeat to West Ham United.