Brentford were unable to repeat their first round penalty spot success when they bowed out of the Johnstone's Paint Trophy to Luton Town on Tuesday night.
The Bees saw off Yeovil Town after a shoot-out following a 2-2 draw in their first round tie at Griffin Park but this time, they were the ones whose luck finally deserted them.
Misses from Josh Wright and Craig Pead brought the night to a sorry conclusion after the home side had missed their third kick to hand the Bees the advantage.
Andy Scott's men looked on course to progress in the competition - which has the carrot of a Wembley final at the end of it - after establishing a 2-0 lead at Kenilworth Road.
Goals from Glenn Poole and Marvin Williams - who was playing up front in a reshuffled side - established a 2-0 lead after 37 minutes.
But the Hatters hit back straight away through Asa Hall and a second half goal from Chris Martin took the match to a spot-kick decider.