Iain Russell scored three minutes after coming off the bench to secure three points for leaders Livingston as they beat Airdrie 1-0.
Kyle Jacobs' shot had hit the bar before the ball fell to David Sinclair. He found Russell, who shot past Mark Ridgers into the bottom-left corner from 12 yards in the 64th minute.
The result was deserved for the visitors, with Raffaele De Vita and Cameron MacDonald both volleying over in the opening half.
Chris Malone drilled a shot straight at Ridgers after the break before De Vita was replaced with Russell in an inspired change after 61 minutes.