A Michael Twiss goal early in the second half gave Morecambe all three points at Griffin Park as they left with a 1-0 win.
The Bees could have been ahead in an entertaining first half but couldn't convert the chances they created and Twiss settled the game with his fourth goal of the season.
It didn't take long for the game to get going; Simon Brown had to produce a fine low save to deny Carl Baker inside the first ten minutes and the same player fired wide soon after.
The visitors started brightly, comfortable on the ball and moving it well, but it was Brentford who had the best chances in the first period.
They should have been ahead inside the first ten minutes when Morecambe's offside trap failed from a Ryan Dickson free kick leaving Matthew Heywood a free header, he nodded down but Lee Thorpe miss-kicked in front of goal and Ross Montague's follow-up was deflected away.
John Mackie, who had to be withdrawn just past the half hour mark, headed over and Sammy Moore tested Joe Lewis in the Shrimps' goal with a long range effort before firing over soon after.
Brown saved well from a Craig Stanley header and The Shrimps had a goal ruled out for offside soon after as they began to gain the upper hand.
Damien Allen fired across the face of goal after a nice move involving Jon Newby and Michael Twiss and then headed over when Baker swung the ball back in but The Bees were creating openings of their own.
A flicked effort from Montague was cleared from inside the six-yard box and the young striker almost opened his Brentford account just before the break.
Glenn Poole's delightful pass set Thorpe free and he forced Lewis into a low save from a fierce shot, the ball re-bounded to Montague but he could only turn it over at full stretch.
The second half took longer to ignite, although Poole tried his luck from distance on a couple of occasions, and it took a Morecambe goal to get the game going.
Adam Yates floated a free kick into the Brentford box, Baker nodded down and Twiss swivelled and turned it home from close range.
The Bees tried to force the pace, Dickson fired a free-kick over the top, Moore fired wide and Craig Pead shot across the face of goal.
But Brown had to be alert to keep Brentford in it at the other end, he saved well to his left to deny Newby and then prevented the same player capitalising on an under hit Ben Starosta back pass.
Brentford could have equalised at the death when Alan Connell produced a fine turn and shot but it flew narrowly wide.
Brentford: Brown; Starosta, Heywood, Mackie (sub Pead 34 mins), Charles; Poole (sub Sinclair 73 mins), O'Connor, Moore Dickson; Thorpe, Montague (sub Connell 56 mins)
Subs (not used): Masters, Shakes
Bookings: Dickson (25 mins) (second of season), Mackie (31 mins) (fifth of season) (suspended for one match, Wrexham, December 15)
Morecambe: Lewis; Yates, Artell, Bentley, Adams; Stanley, Baker (sub Blinkhorn 77 mins), Hunter, Allen; Newby (sub Curtis 84 mins), Twiss (sub Sorvel 90 mins)
Subs (not used): Davies, Howard
Bookings: Stanley (89 mins)
Attendance: 3,155 (117 visiting fans)
Written by Chris Wickham