Dylan MacDonald scored the winner for the hosts
Airdrieonians secured a third straight victory this term to begin their Scottish Championship campaign with victory over last season's runners-up, Raith Rovers.
Dylan MacDonald's close-range header from Lewis McGregor's 75th-minute corner was enough to secure the three points.
Mason Hancock threatened for the hosts and Callum Fordyce for the visitors before Airdrieonians' Ben Wilson came close to his seventh goal of the season only to be denied by the crossbar.
Adam Frizzell also went close for the hosts, but it was MacDonald who secured the win before Hancock and Wilson again went close.
Defeat means Rovers have lost three in the last four games, their only respite being a penalty shoot-out bonus point after a 1-1 draw with Hamilton Academical in the League Cup.
