Stranraer notched a surprise win at Stair Park as Cowdenbeath lost ground at the top of the table.
Stevie Nicholas was the match-winner as he struck in the 33rd minute after latching on to Michael Moore's pass.
Cowdenbeath hit the post through Laurie Ellis in the first half but seldom troubled the home team.
Alex Burns and Mark Crilly shone in centre of the park until the latter was dismissed in the 74th minute for a second caution.
Stranraer: Black, Snowdon, Sharp, Hamilton, Crilly, McAlpine, McKinstry, Nicholas (Lyle 77), Moore (Wright 83), Burns, McMullan. Subs Not Used: McGroaty, Ramsay, Morrison.
Sent Off: Crilly (74). Booked: Crilly, McAlpine, Moore. Goal: Nicholas 33.
Cowdenbeath: Orr, Baxter, Hill, Smith, Ritchie, Fusco (Paul McBride 66), Ellis (Fotheringham 66), Paatelainen, Dalziel (Gomis 36), Clarke, Buchanan. Subs Not Used: Kevin McBride, Hay.
Ref: S Finnie