Alloa ended Hamilton's unbeaten run at the top of the Scottish Championship with a win at Recreation Park.
The league leaders had the better of the early chances, with Alistair Crawford coming close twice within the first 10 minutes.
But the Wasps took the lead a minute before half-time when Alexander Neil deliberately handled inside his own box, leaving referee Kevin Graham no option but to show the midfielder the red card.
Ryan McCord slid home the resulting spot-kick into the bottom right-hand corner.
The 10 men threw all they had at Alloa in the second half but could not manage to create any clear-cut chances, allowing the Wasps to hold on for their third win of the season.
Alloa: Bain, Michael Doyle, Gordon, Marr, Meggatt, Cawley, McCord, Simmons, Holmes (Flannigan 53), Kirk (Robertson 77), McManus (Salmon 84).
Subs Not Used: Young, Tiffoney, McDowall.
Goals: McCord 45 pen.
Hamilton: Cuthbert, Gordon, Devlin, Canning, Hendrie (Finnie 78), Mackinnon, Neil, Gillespie (Ryan 81), Crawford, Antoine-Curier, Keatings (Andreu 77).
Subs Not Used: McShane, Longridge, Currie, Garcia Tena.
Sent Off: Neil (44).
Ref: Stevie O'Reilly