Berwick Ranger crashed to their fifth successive defeat and saw their gate plunge below 300 as their run of poor form continued.
Rangers' defence was heavily criticised by manager Paul Smith last week, but they were caught out by another dreadful blunder when Mark Cowan conceded a free kick.
They were still lining up a wall when Stuart Callaghan chipped into the empty net.
Andy Seaton equalised against his former club with a ferocious 30- yarder, but after Steven Nicholas broke clear on the right he crossed accurately for Iain Nicolson to score with a looping header.
Rangers hope of a revival failed to materialise after Ross Hamilton punished a static defence by cleverly whipping home a slick pass from Michael Daly.
Darren Smith, Berwick's main danger man, put them back into the game with a well- taken goal after 64 minutes when he swept home a pass from Ian Little.
This led to Berwick's best spell of the game, but good save by Gary McGlynn and some fine defending by Iain Nicolson, Robert Walker and Michael Bolochoweckyj saw Alloa through to a well-deserved victory.