He netted after Willie Dyer struck the post for Dundee to put Stenhousemuir through 5-4 after the game had finished 1-1 after 120 minutes.
Goalkeeper Chris Smith also played his part as he saved a penalty by Gavin Rae earlier in the shoot-out which would have put Dundee through.
It was the most dramatic of the three quarter-final ties played yesterday, with Raith Rovers and Annan Athletic joining Stenhousemuir in the semi-finals.
Stenhousemuir showed their menace early in the tie when Kyle Letheren, the Dundee goalkeeper, did well to push a John Gemmelll header onto his crossbar.
But Dundee started the second half on top. Peter MacDonald struck the crossbar with a thunderous shot from distance and just afterwards fired his side in front from the penalty spot after Craig Anderson fouled Jim McAlister.
Stenhousemuir refused to wilt and Sean Higgins netted an assured equaliser against his former club after 62 minutes, Gemmell making the opening.
Neither side could find the winning goal in regulation time or 30 extra minutes, sending the tie to penalties.
Extra-time loomed at Starks Park but Greig Spence came off the bench to score the only goal with barely five minutes left as Raith Rovers squeezed past Falkirk 1-0.
Raith deserved the win on the strength of their second-half performance but Falkirk had their moments and Rory Loy and Phil Roberts were guilty of squandering decent chances. Graham Bowman in the Falkirk goal was the busier keeper, but dealt competently with almost everything that came his way.
As the tie wore on, Raith looked increasingly like winners and so it turned out when Spence scored from close range, leaving Falkirk with little time to retrieve the situation.
Annan Athletic ended Formartine United's fine run in the competition with a 4-0 victory over the Highland League side at Galabank.
The goals all came in the second half after Andy Shearer, the Formartine goalkeeper, had been sent off for felling Kenny Mackay in the penalty area.
Ally Love scored with the resultant spot kick and Annan added further goals through Kieran Brannan, just after he came on as a substitute, Mackay, and then David Hopkirk.