In only his second Stenny appearance since his January move from Arbroath, the striker netted in the first and last minutes of a thrilling contest at Borough Briggs.
In between, Davie Irons team let a two-goal lead slip and could easily have slid to defeat but for a late revival culminating in Spence’s vital stoppage time winner.
Irons handed a debut to 19-year-old midfielder Callum Moore who was brought in on loan from Dundee and started ahead of Alan Cook in the only change from the 2-2 draw with Brechin a week earlier.
The travelling Stenny fans could not have hoped for a better start as their team drew first blood 60 seconds after kick-off.
Elgin were pressed back from the start and Brian Cameron’s attempted clearance cannoned off a Stenny player and ran through for Spence, who wasted no time in crashing a fine shot high past keeper Tom McHale.
The home side responded well with top scorer Shane Sutherland, who has signed a pre-contract to join Caley Thistle in the summer, inches away from equalising with an angled drive.
Moore didn’t take long to show why Irons brought him in, skinning Elgin full-back Rory MacEwan down the left before playing a tantalising ball across which David Hopkirk couldn’t connect with at the far post.
Moments later Mark McGuigan played Moore into the box and the teenager had the target in his sights but made the wrong decision to instead try to set up Spence and a home defender was able to clear.
Stenny withstood some wind-assisted pressure from the north side and doubled their lead on 37 minutes.
Elgin failed to clear their lines and Ryan Blair smacked in a shot which McHale saved at full stretch, and the keeper also blocked McGuigan’s follow-up but a third attempt from McGuigan landed up in the back of the net.
Two-up at the interval, Stenhousemuir had an opportunity to kill the contest off five minutes after the break when Moore picked out Hopkirk with a left wing cross but from point-blank range, Hopkirk couldn’t keep his header down.
Graeme Smith was in action at the other end, diving to his left to repel a Rabin Omar shot and when the ball ricocheted back to Elgin winger Conor O’Keefe, the Warriors keeper had to repeat his save at the near post on 61 minutes.
Elgin were now piling on the pressure, and Irons gave McGuigan a well-earned rest to introduce the lively Botti Biabi, who soon broke away to create an opening which Hopkirk dragged wide of the target.
It looked like Stenny might hold on for a clean sheet when, out of the blue, City turned the game on it’s head with two goals in two minutes.
On 78 minutes a speculative 30-yard effort by home sub Daniel Mackay took a deflection to deceive Smith and loop into the net.
Buoyed by their breakthrough goal, Elgin pushed for a second and were controversially given a corner after Sutherland was flagged offside before winning a corner kick, but ref Chris Fordyce waved away his assistant’s flag.
The kick led to a second corner and when the visitors failed to clear, the ball fell to Elgin centre-back Stephen Bronsky to guide a shot beyond Smith into the net.
Smith was also booked for a clash with Elgin’s Cameron, and the game seemed to be slipping away from the Warriors until they regrouped and came up with a priceless winner.
Sub Connor McBride threw himself at a ball into the box and nodded it into the patch of Spence who had time and space to sweep it past McHale.
There was little time for City to chase a third goal, and the final whistle was greeted with jubilation by the Stenny camp as reward for a battling success against the odds.