Kidderminster came out on top of a thrilling cup tie with a dramatic Golden Goal winner after having found themselves two goals down early in the second half.
Both teams approached the game looking for victory and exchanged chances in an even first half before Danny Invincibile held off the challenge of Abdou Sall to tuck a shot inside the near post to give the visitors the lead seven minutes before the break.
The game sprang to life after the interval, Alan Young capitalised on a defensive mix-up to put Swindon two up, but within seconds JJ Melligan had struck to bring Harriers back into the game.
A minute later Drewe Broughton forced the ball in from close range to equalise and both teams had good chances to win the game but were unable to capitalise.
In extra time Sam Parkin thought that he had won the game for Swindon, but his goal was ruled out for offside and then just as the first period of extra time was coming to an end, Sall dived in to head home Sam Shilton's corner to send the home team into the third round