The sending-off of on-loan Rangers midfielder Paul Emslie after just seven minutes on the pitch was to prove crucial as Peterhead crashed to defeat in what Neale Cooper had previously billed a "must-win" game.
Emslie's moment of madness came short
ly after he had replaced Neil McVitie, and left the Blue Toon a man down against the league leaders for more than half the match.
Having been humbled by Brechin at Balmoor in their last outing a fortnight ago, Peterhead lined up on the artificial surface at Recreation Park with Bobby Mann restored to the side alongside Jonathan Crawford in defence, while club captain Callum Macdonald was on the bench after a lengthy spell on the sidelines.
Recent signing Conor Gethins was also on the bench, while midfielder Nicky Clark was passed fit to play in a protective cast, despite sustaining a wrist injury in an awkward fall in the defeat to Brechin.
It was a nervy start for the Toon, not aided when McVitie seemed to leave a long ball for goalkeeper Paul Jarvie early on, only for the goalkeeper not to come and collect. A brief panic set in before McVitie recovered to clear for a corner.
Moment of madness: Paul Emslie's swipe at Alloa's Prunty saw him red carded
Alloa had the brighter opening period, although Peterhead looked dangerous on the break, as shown when Barry Wilson and Davie Donald led a counter-attack after 10 minutes, the promising move breaking down as Wilson failed to pick out a Peterhead player with his cross from the right.
Moments later, McVitie's ball found Martin Bavidge on the edge of the box but the striker's attempted left-foot effort on the turn was weak and Alloa keeper David Crawford was comfortably able to mop up for the hosts.
The Wasps' Stuart Noble has a good record against Peterhead, and he came close to adding to that when he flashed an effort across the face of goal from the left side of the penalty area.
And his strike-partner Bryan Prunty could have opened the scoring when a great move down the left saw John Grant combine with Gary Carroll and David McClune before the ball was played in from the left.
Prunty was the target, but the former Celtic and Aberdeen man mis-timed his header, and ended up heading away from goal, easing the pressure on the Toon.
Alloa were stepping up the pressure, and defender Mark Brown saw his header flash over, before Paul Jarvie twice saved from Prunty in as many minutes.
Their persistence paid off, as Noble finally gave them the lead after 29 minutes. The striker latched onto a neat through-ball and steadied himself before drilling a low shot beyond Jarvie and into the bottom-left corner of the net.
Emslie replaced McVitie shortly after, and Peterhead were level before his red card all-but ended their chances of a win.
There was a blow for the Toon when Davie Donald was forced off through injury
The equaliser came when Donald cut-back superbly for the onrushing Clark, and he drilled in from close range to level the scores.
Clark attempted to put his side in front just two minutes later, but his 25-yard shot found only the side-netting as Peterhead briefly came back into the game.
But Emslie's petulant swipe at the grounded Prunty five minutes before the interval gave referee Craig Charleston no option but to reach for his top pocket, and all-but extinguished Peterhead's hopes of going on to win.
To their credit, the Toon battled on despite their numerical disadvantage, but all too often their out consisted of long balls towards the isolated Bavidge, which gave little chance of being able to hold onto the ball for any period.
There was another blow for the Toon when Donald was forced off through injury his place taken by Macdonald, with Crawford switching to the right-back slot.
Despite the hosts having much of the possession thereafter, they struggled to test Jarvie, though Noble should have done better with the goal gaping after neat play down the left had seen the keeper drawn to his near post.
When what proved to be the winner finally came after 78 minutes, there was an element of fortune about it. Noble's pass set up Andy Scott, and the attacker lashed a shot on the half-volley beyond Jarvie, aided by a deflection off the luckless Macdonald.
