Two goals in two minutes in the dying stages meant Brentford were beaten by Colchester United.
The Bees looked to be in complete control with ten minutes remaining and lead through a Niall McGinn goal but Steven Gillespie scored in the 83rd and 85th minute to give his team the spoils.
The first quarter of the match was fairly even - Brentford hit the post early on but Colchester were able to turn the visitors' defence on occasion and won some dangerous set pieces.
McGinn and Myles Weston were at the heart of things for Brentford, as the wide men in an attacking three that looked to stretch the Colchester defence.
The two combined with a short corner that set McGinn free, he got to the by-line but the cut back was blasted wide by Leon Legge under pressure.
McGinn went even closer soon after when he cut in off the left and curled a right footed shot that beat Ben Williams all ends up but cannoned away off the outside of the post.
That was the closest either team came in an opening half hour that saw plenty of action in the penalty areas but few moments to worry the goalkeepers.
Karl Duguid, playing his 400th game for Colchester, shot wide when well placed and Magnus Okuonghae headed a miss-cued Brian Wilson shot off target.
Lloyd James blasted a free kick wide for the home side and then missed the target from distance while Anthony Wordsworth also shot over.
Colchester's best chance of the first half came when a cross from Wilson was only half cleared, Kem Izzet's shot fell to Ian Henderson and Richard Lee had to be smartly out to save at the striker's feet.
Weston and Toumani Diagouraga had shots blocked but Colchester would probably have gone in at half time happier.
Particularly as they escaped a few moments before the break when McGinn played the ball past the home defence and appeared to be through on goal only for the flag to go up for offside against Gary Alexander, who had peeled away from play and was clearly not interfering.
Referee James Linington backed his colleague and McGinn's chance to race through was taken away.
Brentford started the second half well and by the time McGinn gave them the lead just before the hour, they merited it.
McGinn fired a near post shot wide on one early second half attack and The Bees pressed their hosts back.
The goal came following the award of a penalty won by Jake Bidwell, he exchanged passes with Weston and darted in to the box before Duguid clipped his heels and Mr Linington pointed to the spot.
Alexander blasted his penalty down the middle but Williams stood firm and kept out only for Diagouraga to head down for McGinn to lash in from 17 yards with his left foot.
Brentford dominated the first half of the second period and could have wrapped the game up - McGinn shot wide and Jonathan Douglas blasted a free kick over.
The Bees were bossing the midfield and Colchester had almost no possession with which to try and fashion a leveller.
It was Brentford who looked most like scoring - Alexander had a shot blocked and when McGinn put the loose ball back in, Sam Saunders could not convert.
Saunders had a low free kick saved by Williams but a set piece at the other end almost gave Colchester a way back in to the game.
Substitute Martin Rowlands delivered a free kick from the right and Tom Eastman rose highest but the central defender headed wide from eight yards.
That gave the home side a boost and they pressed hard for an equaliser.
Douglas deflected an Henderson shot wide and Bidwell blocked an effort from Kayode Odejayi before Lee saved an Okuonghae header.
The momentum of game had shifted and Colchester got their equaliser when Henderson fired a shot against the bar after exchanging passes on the edge of the penalty area and Gillespie bundled home the loose ball.
Odejayi blasted wide soon after and seconds later, Gillespie let fly with a shot that seemed to swerve and dip past the dive of Lee to complete the turnaround.
The Bees were shell-shocked, they had gone from complete command to behind in almost the blink of an eye and there was no way back.
They had a chance when Alexander met a Saunders cross with a looping header but Williams held it and Colchester took the points.
Colchester United: Williams; Wilson, Eastman, Okuonghae, White; James (sub Gillespie 67 mins), Izzet (sub Rowlands 70 mins), Wordsworth; Massey, Henderson, Duguid (sub Odejayi 59 mins)
Subs (not used): Bond, Coker
Bookings: Duguid (56 mins), Wilson (59 mins), Rowlands (76 mins)
Brentford: Lee; Logan, Legge, Dean, Bidwell; Bean (sub Berahino 88 mins), Diagouraga, Douglas; Weston (sub Saunders 67 mins), Alexander, McGinn (sub Donaldson 82 mins)
Subs (not used): Thompson, Balkestein
By Chris Wickham