Falkirk scored three minutes from time to earn a vital victory over second-placed St Johnstone and maintain their 100% home record.
The Bairns had kicked off with a four-point advantage at the top of the First Division and they controlled long periods of the first half with Owen Coyle and Lee Miller both going close.
The home side should have taken the lead moments after half-time when the ball was spilled by goalkeeper Kevin Cuthbert but Miller was unable to force his shot into the net.
However, with time running out, Falkirk captain Kevin James pounced with a header to move the hosts seven points clear at the top.