Cowdenbeath made a superb start to their Second Division campaign.
Last season's Third Division champions were 2-0 up after 13 minutes thanks to two headers from Scott Dalziel.
Alloa pulled a goal back two minutes after the interval with a curling shot by Ross Hamilton but Liam Buchanan's strike restored the two-goal cushion.
Pat Scullion struck from a tremendous free-kick and Markus Paatelainen got into the act with a double in the 59th and 60th minutes.
Cowdenbeath: Orr, Guy (Fotheringham 81), Ritchie, Smith, Ellis, Patrick Scullion (Baxter 58), Gomis, Paatelainen, Clarke, Dalziel (Paul McBride 70), Buchanan. Subs Not Used: Kevin McBride, Allison.
Sent Off: Ritchie (83). Booked: Clarke, Ellis. Goals: Dalziel 10, 13, Buchanan 55, Patrick Scullion 58, Paatelainen 59, 60.
Alloa Athletic: Greer, Bolochoweckjy, Townsley, Malcolm, Clark (Thomson 2), Hamilton, Grant, McAnespie, McCalum (Trialist 64), Sloan, Brown (Hazeldine 64). Subs Not Used: Forest, Hutton.
Booked: Grant, Thomson, McAnespie, Hamilton. Goal: Hamilton 47.
Ref: E Norris