brentford and dagenham & redbridge shared 12 goals in the joint highest scoring league cup tie in history.
the match was 4-4 after 90 minutes and 6-5 in extra-time before brentford's harlee dean scored late on to take the match to penalties.
jack connors and ashley chambers missed for the daggers with bees skipper kevin o'connor scoring the winning spot-kick.
the only other tie to have witnessed that number of goals was reading 5-7 arsenal in 2012.
stuart dallas scored twice early in the match to put brentford in control. george porter pulled one back for the daggers, before nick proschwitz took advantage of indecisive home defending to make it 3-1.
chambers reduced the deficit once more and then andre boucaud struck from 25-yards to pull the east london side level.
substitute andre gray made it 4-3 to brentford, but in the last minute of the 90 ashley hemmings scored from an acute angle to force extra time.
montell moore, 18, put the west london side back in front, but jamie cureton, 20 years his senior, made the scores level again.
dagenham went in front for the first time with seven minutes remaining through hemmings, but they were denied three minutes later when dean headed in.
since joining the football league in 2007, dagenham & redbridge have never made it past the first round of the league cup.
dagenham & redbridge boss wayne burnett:
"after 10 minutes ı thought this was going to be an onslaught but we showed really good character to get back into the game.
"we scored some decent goals and ı am pleased with that - and if you score six goals you expect to win the game but ı am disappointed in the manner in which we conceded some of the goals.
"ıt was very unlike our defence but we showed real good character and work ethic. ı am so proud. at 6-5 you hope you can see the game out but the state of this game was unbelievable.
"ı can't remember being involved in a game like it."
brentford boss mark warburton:
"ıt's embarrassing being ahead on so many occasions and not seeing the game out, but we'll come back and learn from it.
"we could have had a lot more goals than we did and to then suddenly concede one just before half-time through some sloppy defending and poor defending; ı am not sure ı have seen anything like that before in my time in the game.
"we will learn from it though and there were some positives in terms of the youngsters like montell moore who is out on his legs."
