Scott McBride struck decisively 19 minutes from time as East Fife overcame a second-half fightback from Stenhousemuir to secure a memorable 3-2 triumph.
Robert Barr gave the Fifers a dream start when he collected McBride's header down to thump an unstoppable effort into the top corner from 30 yards.
Steven Campbell doubled the advantage with 32 minutes played when he headed home Jamie Pollock's cross from close range.
Stewart Kean steered Bryan Hodge's corner over the line 12 minutes after half-time to hand Stenhousemuir a lifeline and a set-piece from the same player allowed Andrew Rodgers to level matters in the 69th minute.
But two minutes later, McBride headed Paul Willis' cross from the left past Callum Reidford in the Warriors goal to move East Fife above their opponents and into the final play-off spot.