Town made three changes to their starting eleven that beat Maidstone on Sunday evening. Keeper Artur Krysiak and Jakub Sokolik missed the trip through suspension and were replaced by Chris Weale and Alex Lacey.
Ryan Dickson also missed the trip through a slight knock and was replaced by Harry Cornick. Top scorer Ryan Bird was rested to give a start to Shaun Jeffers.
Town started the game very brightly and had the first chance of the game after just three minutes when a Dolan header found Fogden in the area, the goalscorer from Sunday found Sowunmi at the back post, but his header went across the face of the goal and Gillingham managed to clear.
Two minutes later a sloppy clearance from Nelson in the Gills goal was picked up by Tozer just inside the Gillingham area. The former Northampton man looked up pinged the ball towards goal. With Nelson tracking back and in no mans land the ball came back off the bar and Sowunmi could only hot his effort into the ground.
Town took a deserved lead on 13 minutes when Cornick picked the ball up on the left wing and ran at John Egan, the defender slipped over after Cornick sold him a dummy and with just the ‘keeper to beat the Bournemouth loanee curled the ball around Nelson to make it 1-0 to the Glovers.
The home side started to get back into the game after the Glovers took the lead, but failed to really test Weale in the Town goal. The Yeovil shot stopper looked confident when punching clear from Gillingham corners.
Two minutes before the break and slightly against the run of play the home side drew level. A cross from the right was half cleared by Town, but the ball fell to Garmston, who controlled well on the corner of area to cut in onto his right right foot to unleash an unstoppable shot past Weale and in to far corner of the net.
Town started the second half on the front foot and had the first chance of the second period. Superb close control on the edge of the area from Jeffers saw the striker lay off to Cornick, but his shot from ten yards sailed over the bar and into the empty stand behind the goal.
With just over twenty minutes to go the Glovers made their first change with Sowunmi being replaced by top scorer Ryan Bird.
The Glovers had a great chance to re-take the lead on 76 minutes when Darren Ward headed a Dolan free kick back across goal into the path of Lacey, but the centre back could only fire over the bar.
With three minutes of added on time being signaled Dack’s shot from the edge of the area was well saved by Weale.
Deep into injury time, Weale was called into action to deny a goalbound Loft effort. If his shot had gone in the roof would have been lifted off.
The game went to penalties and with everyone scoring before Gillingham’s fifth penalty in which Donnelly skied over. It was left to Roberts to take the fifth Town penalty. He stepped up confidently to fire home and send Town through.