The Bees winless run at The Matchroom Stadium continues after Kevin Lisbie and Jimmy Smith's goals gave the home side all three points. Brentford have yet to secure three points in a League fixture there since April 1995, with two damaging set piece goals in the first half condemning the visitors to another away defeat. it was a disappointing display in front of a large travelling support, which saw their side dominate the opening exhanges but slip to a defeat that puts a play-off place now surely out of reach.
Manager Uwe Rösler selected a 4-3-3 formation, with loan signings Berahino and McGinn on either wing, playing Clayton Donaldson down the centre. There was also a place on the bench for development squad striker Antonio German, a January window signing from Bromley.
Brentford started the brighter of the two teams, and should have taken the lead twelve minutes in. However, Saido Berahino shot wide from close range after Orient goalkeeper Paul Rachubka spilled Niall McGinn's goal bound effort in the six yard box. This was not the end of The Bees' spell of pressure, a pin-point Jake Bidwell cross found Leon Legge - his header could only find its way to the grateful arms of Rachubka.
As in recent games away from Griffin Park, the failure to capitalise on these dominant spells paid dearly, and Orient edged ahead in the 29th minute. From a left-wing Cox free-kick, striker Kevin Lisbie rose above a clutch of Bees defenders to head past Moore.
Undeterred, Brentford kept attacking; Niall McGinn's 33rd minute header was well saved from Rachubka, Berahino again the provider. The second - and killer blow - arrived seconds before half-time; Jimmy Smith's found himself with plenty of space, his right foot shot beating Moore, which left Brentford two goals down.
Uwe's response was swift at the break, replacing Berahino and McGinn for German and Forrester respectively. The latter could have pulled a goal back sixty seconds into the second half but his effort was scrambled away for a corner.
In truth the match appeared lost at half-time, for all their endeavour, Orient restricted Brentford to a Douglas half-volley that skied over the bar and a smart shot from Bidwell that went wide of Rachubka's left-hand post.
Leyton Orient: Rachubka; Forbes, Cuthbert, Chorley, McSweeney; Reed, Spring; Jimmy Smith, Campbell-Ryce (sub Mooney 73 mins), Cox; Lisbie (sub Ben Youssef 89 mins)
Subs (not used): Lovelock, Laird, Jamie Smith
Bookings: Forbes (83 mins)
Brentford: Moore; Logan, Bidwell, Dean, Legge (sub Osborne 71 mins); Forshaw, Diagouraga, Douglas; McGinn (sub Forrester h/t)); Donaldson, Berahino (sub German h/t)
Subs (not used): Lee, Thompson
Bookings: Logan (40 mins) (second of season), Donaldson (64 mins) (second of season)