Newport Pagnell Town boss Darren Lynch thought his side were heading for extra time when they conceded a late equaliser against Newbury Forest on Saturday before a stoppage time winner saw them progress.
In a dramatic afternoon at Oakside Stadium, Swans looked to be heading into the next round as they went into the final minute with a 2-1 advantage, thanks to goals from Dom Lawless and Liam Smyth.
But a lapse in concentration allowed Forest back into the affair in the 90th minute, with extra time on the cards. There would be one final twist though as Newport won a free kick in the 94th minute, and picked out Jake Wilkinson at the far post to head home the winner and book their spot in the second round.
"(It was) a chance for us to put aside our terrible start to our league campaign," said Lynch afterwards. "I thought we managed the game really well but a second of lost concentration looked to be taking the game into extra time when their striker equalised in the 90th min.
"But we got a freekick on the right hand side and with literally the last kick of the game, Smyth’s perfectly delivered ball was headed in at the back post by young Jake Watkinson who had come on as sub not too long before!
"I honestly think we deserved the win on our performance but they will be very disappointed considering they equalised so late on."
Newport host Deeping Rangers at Willen Road on Saturday as they desperately seek a win in UCL Premier.