Airdrie turned on the style to thump Montrose as they closed in on League One leaders Cove Rangers.
With Paul Hartley's side held to a draw, Airdrie closed the gap at the top to five points and stretched their lead over third-placed Montrose to four points.
Calum Gallagher's first-half double was halved by a Graham Webster penalty, but though the visitors started the second period as the better side, Airdrie soaked up the pressure and struck decisive blows via sub Craig Watson and Adam Frizzell.
