Sky Bet League One leaders Leyton Orient came to Griffin Park and left with their eighth win in eight league games thanks to two second half goals.
The visitors had to withstand a great deal of pressure from Brentford, particularly at the start of the second half.
But their defence, superbly organised, weathered it and they took the chances when they came their way.
David Mooney fired home from the penalty spot to give them the lead and substitute Shaun Batt made it safe late on.
As would befit a team that had won their first seven league games, Orient came to try and play.
They were happy to go forwards, commit numbers and try and support their front pair.
It meant the Griffin Park crowd, and the Sky Sports audience, was treated to a fine game.
While there was no early breakthrough, it was not for want of trying.
Kevin Lisbie bounced a shot wide early in for the hosts before Harlee Dean headed an Adam Forshaw free kick off target when well-placed.
Forshaw was at the heart of most of Brentford’s good early play and alongside Alan McCormack and Toumani Diagouraga in the centre of midfield, helped The Bees take control.
Nathan Clarke made a firm challenge – deemed fair in the eyes of referee James Linington – to prevent Dean scoring after he burst forward and played a one-two with Will Grigg and Orient goalkeeper Jamie Jones saved a low Forshaw free kick soon after.
Moses Odubajo shot wide for the visitors but most of the action was at the other end.
Forshaw curled a shot wide from 25 yards and then forced Jones in to a low save from a free kick before Martin Fillo headed straight at the Orient goalkeeper.
Brentford would probably have felt they had the better of the first quarter but Orient had the best chance.
A free kick was half cleared and Odubajo crossed to the far post, Mooney rose highest but headed over from six yards out.
Jones denied Clayton Donaldson after a sharp turn before a long throw caused chaos in the Brentford penalty area, it bounced all the way through and Martin Taylor could only hack it as far as Mooney, who turned a shot over from ten yards.
Dean smashed a shot over the bar from a low Forshaw corner but the game started to lose its flow as half time approached.
Orient were penalised on numerous occasions by Mr Linington and any attempt Brentford had to build momentum was hampered by number of free kicks.
Mooney shot wide for the hosts before Donaldson almost snatched a goal at the end of the first half.
It came when Richard Lee sliced an attempted clearance and Dean came across to help him out, he played a long ball forward that caught everyone out and set Donaldson in behind the defence, he appeared to get a tug on his shirt from Mathieu Baudry as he attempted to shoot and sliced his effort wide while Mr Linington waved play on.
The striker shot just over after a fine turn at the start of the second half and a low Forshaw free kick fizzed across the six-yard box before it was rather fortuitously scrambled away.
The Bees started the second period well and were dominating in terms of territory, possession and chances.
A Donaldson shot deflected wide after he won the ball well off Romain Vincelot and from the resulting corner Clarke made a miraculous block to deny Tony Craig.
Donaldson had a pair of headers saved as Brentford started to go through the gears and Clarke, in particular, was working overtime to keep them at bay.
However, the visitors then hit The Bees with a sucker punch.
A long ball forward beat Dean and Lisbie and Mooney tussled with Shaleum Logan, Mr Linington decided the Brentford defender had committed a foul and awarded a penalty.
Mooney fired it low to Lee’s right to give Orient the lead.
Lee had to tip a fierce Odubajo shot over the bar to stop him making it two seconds later as the visitors grew in confidence.
Brentford tried to respond and McCormack and Diagouraga both shot wide before Manager Uwe Rösler brought on attacking trio Joao Teixeira, Marcello Trotta and Stuart Dallas to try and take the game to Orient.
But they couldn’t get anything going and Orient made the game safe with five minutes remaining.
After nice interplay in midfield, the ball was slipped through to Batt, he raced clear and slotted past Lee to seal the win.
A Trotta shot hit Donaldson after good work involving Dallas and a Donaldson header was blocked but Brentford had little response.
Diagouraga had a shot blocked, as did Dean and Teixeira and Taylor missed the target as The Bees pressed but Orient held firm.
Donaldson could have pulled one back and Forshaw played him through in the inside left channel but he slipped as Jones rushed out and the goalkeeper gathered.
That was Brentford’s last chance to salvage something from the game and Mr Linington blew up after six added minutes to confirm the continuation of Orient’s winning run.
Brentford: Lee; Logan, Dean, Taylor, Craig; McCormack (sub Dallas 75 mins), Diagouraga, Forshaw; Fillo (sub Teixeira 69 mins), Grigg (sub Trotta 74 mins), Donaldson
Subs (not used): O’Brien, O’Connor, Reeves, El Alagui
Bookings: Diagouraga (52 mins), Logan (64 mins), Dean (88 mins) (second of season)
Leyton Orient: Jones; Cuthbert, Baudry, Clarke, Omozusi; Odubajo, James, Vincelot, Cox; Lisbie (sub Batt 82 mins), Mooney (sub Bartley 89 mins)
Subs (not used): Larkins, Sawyer, Lasimant, Gorman, Stockley
Bookings: Baudry (73 mins), James (78 mins)
Attendance: 6,439 (893 away fans)
By Chris Wickham