Kyle Connell hit an 80th-minute winner as Airdrie inflicted a first Scottish League One defeat of the season on leaders Falkirk.
The on-loan Kilmarnock striker netted the only goal at the Falkirk Stadium to push Airdrie up to fourth in the table.
The hosts had the better of a quiet first half with Robbie Leitch having their best chance saved.
Airdrie improved after the break though and Connell was denied from a good chance before later converting the rebound after Robbie Mutch had stopped Paul McKay's header.
