Substitute Luke Donnelly grabbed the only goal of the game to give Alloa a slender advantage in their cinch Championship play-off against Hamilton.
Donnelly came off the bench after just 25 minutes following a serious-looking injury to Adam King, who went down off the ball and was taken off the pitch on a stretcher after receiving treatment.
That led to five minutes of added time in the first half, during which the ball broke for Donnelly who rifled home.
Reghan Tumilty almost hit straight back for the visitors, who are looking to preserve their place in the second tier after their ninth-placed finish, but saw his effort canon back off the crossbar.
It remained a tightly-fought match during the second half, with Quinn Coulson close to making it 2-0 when he was denied by the frame of the goal.
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