Brentford reached the Southern Area semi-finals of the Johnstone`s Paint Trophy after claiming a 4-2 win on penalties after the game ended 1-1.
Robbie Simpson converted the winning spot-kick which meant the Bees stretched their unbeaten run to seven games in all competitions.
Swindon controlled the opening period, and their dominance paid off after 13 minutes when Charlie Austin beat the offside trap and poked the ball home for his ninth of the season.
Brentford showed very little in the first half but Simpson equalised against the run of play. A superb cross from Craig Woodman on the left found Simpson unmarked at the back post and the striker headed home eight minutes before half-time.
Chances were at a premium in the second half, with Austin having the only real effort when he somehow missed from three yards out with only Brentford defender Pim Balkestein on the line.
The shoot-out saw Swindon`s David Ball hit the crossbar and Michael Timlin blaze well over. Phil Smith saved from Craig Woodman to give Swindon hope, but Simpson slotted home the last spot-kick to send Andy Scott`s men through.