Steve Jenkins was booked for the 10th time this season and will miss the Notts County match and the first leg of any Play-off semi-final they might play.
With events elsewhere going against them today, the play-off situation is far from clear and the Terriers go into the Cardiff game with Leon Knight still treading the disclipinary tightrope and injury doubts to Danny Schofield (groin) and Dwayne Mattis (leg).
The match itself was little short of a disaster for Town as they were polished off by the Bees within 40 minutes of this encounter.
Brentford started as expected, with a long ball bombardment and plenty of physical threat all over the field.
Paul Evans, the Bees midfielder, signalled some serious intent when he had Margetson backpedalling in order to tip his rasping shot away after just 8 minutes.
It might have been a different story had Leon Knight's early 'goal' counted.
The little Chelsea striker had an appetite for the game and deflected John Thorrington's teasing shot/cross into the back of the net after 18 minutes but it was disallowed for offside.
That was just about Town's last decent attempt on goal as Brentford stepped up a gear and rolled the Terriers over.
Paul Evans sent in another great delivery from a set piece after 26 minutes and Lloyd Owusu couldn't believe his luck after Martyn Margetson spilled the ball out of his hands.
The Brentford goal machine stabbed the ball home for a scrappy goal, a theme for the rest of the half, with the Town defenders standing around him.
Owusu turned provider just 8 minutes later when he strolled past some slack defending and fed Steve Sidwell for a bobbling strike which rolled past Margetson's near post.
Town were in total disarray by the time Ijah Anderson crossed for Martin Rowlands who drew Margetson off his line before pulling the trigger for 3-0 it was all over in the 38th minute.
The Bees took their foot off the pedal for the second half but that didn't seem to matter as Town's wheels had fallen off.
The Terriers continued to play to Brentford's strengths with poorly aimed long balls up field combined with one dimensional play and very slack marking.
The introduction of Andy Booth made little difference as Lou Macari retained a relavtively cautious outlook to the match and, as injuries took their toll on the Terriers, watching Town fans must have wondered how they were going to cope with Cardiff without two key midfielders.
Read Mel Booth's full match report in the Examiner on Monday. Have your say in the messageboard below. Selected messages will be considered for publication in the Examiner - please use your full name and location.
Brentford (4-4-2): P Smith, Dobson, Anderson, Ingimarsson, Powell (Theobald 88), P Evans, Sidwell, Rowlands (Boxall 71), Owusu (McCammon 80), Burgess, Hunt
Subs not used: Gottskalksson, O'Connor
Scorers: Owusu 26, Sidwell 34, Rowlands 38
Town (4-4-2): Margetson, Jenkins, Evans, Gray, Clarke, Thorrington, Mattis (Heary 83), Irons, Schofield (Booth 47), Knight, Facey
Subs not used: Hay, P Evans, Moses
Referee: Clive Penton (East Sussex)
Attendance: 7,393 (Estimated 1600 Town fans)
Match points follow on subsequent pages
91 mins: 4 minutes of added time were awarded but there was little point in playing as Brentford began to showboat.
90 mins: Clarke nearly gave the ball away in a critical position but he recovered.
88 mins: Thorrington was surrounded by 4 Brentford defenders as he tried to make the most out of a counter-attack.
85 mins: Mattis was led off, limping, by Alex Moreno and was replaced by Thomas Heary as Town stumbled towards the finishing line.
83 mins: Dwayne Mattis was down and needed treatment after winning the ball from Ben Burgess.
82 mins: Home fans were singing as the game slowly edged towards 90 minutes.
80 mins: Paul Evans hit a set piece against the bar with Margetson at full stretch and saw Burgess waste the follow-up!
79 mins: A very poor match for Town was begining
75 mins: Dobson outmuscled Thorrington as Brentford continue to outplay the Terriers. The second half seemed slower, as the Bees assumed that they had lready won the match.
72 mins: Rowlands went off and was replaced by Danny Boxall.
70 mins: Owusu's effort was over the bar.
68 mins: Town were still second best as Ingimarsson's pass found Owusu in a dangerous area before being tackled by Gray.
65 mins: Knight needed treatment for his fall.
64 mins: Booth's header was wide and fell to Knight who was fouled in the area as he tried to nip behind his marker. The referee conferred with the linesman and gave an indirect free kick inside the penalty area for obstruction which was wasted by Irons.
63 mins: Andy Booth's terrible backpass needed Margetson to be quick to collect with Owusu lurking.
57 mins: Darren Powell cleared after Facey had beaten the offside trap.
56 mins: Knight's cross was palmed away by Smith - away from danger.
54 mins: Rowlands had a strike fly over the bar. The Town defence were arguing with each other after slack marking allowed Brentford plenty of space down the flanks.
49 mins: Town were saved by Margetson who palmed away a goalbound free kick from Paul Evans which had whipped in past the wall.
47 mins: Margetson watched Dobson's cross go out of play with Hunt running after it despairingly.
46 mins: Danny Schofield limped off with what looked like a groin injury and was replaced by Andy Booth as Town reshuffled right at the start of the second half. Thorrington was switched to the left, Knight went to the right and Andy Booth joined Delroy Facey up front as Lou Macari stuck with 4-4-2.
A very poor first half saw Owusu, Sidwell and Rowlands score a trio of sloppy goals as they outcompeted the Terriers in all areas of the pitch. Only Leon Knight showed any hunger and his deflected goal was disallowed for offside as Town seemingly ignored Brentford's rather obvious strengths and pumped long balls upfield which were easily picked off by the Bees defence.
43 mins: Burgess and Owusu were getting plenty of service as Town were very poor.
38 mins: Rowlands touched the ball past a Town defender and drew Margetson before finishing past him with aplomb from Ijah Anderson's splendid cross.
37 mins: Another lifted cross to the far post by Brentford was cleared but Schofield wasted possession and allowed Brentford to attack again.
36 mins: Rowlands' show sizzled wide after Town were again poor and conceded possession.
35 mins: Steve Jenkins received his 10th yellow card of the season for a poor tackle and knew he would be suspended for 2 games (Notts County and Play Off Semi Final 1st Leg).
34 mins: Margetson couldn't reach the ball after Steve Sidwell's bobbling strike rolled past him and into the net following a mistake by Gray.
33 mins: Irons' floating free kick was cleared as Thorrington tried to reach it.
33 mins: Knight went down after a challenge but the referee waved away appeals.
32 mins: Thorrington's corner was cleared by Rowlands.
30 mins: Knight received the ball from Margetson and took on the Bees defenders until he was fouled by Ingimarsson. Jenkins' fiery shot from Thorrington's rolled free kick flew over the bar.
28 mins: The Bees were lifted by their goal and were winning everything on the pitch.
26 mins: A scramble in the six yard box ensued from Paul Evans' delivery and Lloyd Owusu pounced after Margetson appeared to spill the ball - the Town defenders could do nothing but watch the ball trickle over the line.
23 mins: Clarke defended well and saw Thorrington was free before setting him up.
22 mins: Burgess' shot on the turn was wide as the Bees pressurised.
21 mins: Hunt's teasing cross was cleared by Evans for a corner.
18 mins: Thorrington's run and shot from Margetson's clearance saw the ball take a deflection off Leon Knight and into Brentford's goal. The lightning counter-attack caught the Bees by surprise but the goal was disallowed because Knight was adjudged offside.
17 mins: Sidwell's run and shot was wide of Margetson's goal.
16 mins: The game was beginning to settle down as the Terriers got the measure of their opponents.
11 mins: Thorrington's set piece almost fell for Clarke before a period of pressure saw Brentford clear the ball.
9 mins: Dobson's touch from the corner sparked a panic before the Terriers cleared the ball.
8 mins: Evans whipped in a tricky ball which a backpedalling Margetson had to tip over the bar from the set piece.
6 mins: Town were sitting deep and trying to hit Brentford on the countr-attack using the pace of Thorrington and Knight.
5 mins: Thorrington's corner was repelled by Brentford.
4 mins: Margetson blocked a Bees strike as Town struggled to make an impression.
2 mins: Brentford's long ball bombardment continued and Town were under pressure. Paul Evans struck the ball at Margetson's goal but it flew wide.
1 min: Brentford scythed their way through Town's defence from the start. Clarke gave away a free kick but the Town wall held firm while Thorrington cleared.
Lou Macari named an unchanged side as he gambled on Leon Knight not getting suspended against a strong Brentford side.
Dangerman Ben Burgess made a surprise return to fitness for the game against the Terriers.