A James Craigen goal was enough to settle a keenly contested affair as Falkirk stayed in play-off contention and sent Ayr to a third consecutive defeat.
The Bairns had an early chance when Luke Leahy fired just wide from the edge of the box. But the opener did arrive on 15 minutes following a sweeping move which saw John Baird and Aaron Muirhead combine for Craigen to shoot firmly into the net.
The Honest Men rallied briefly but failed to test Danny Rogers in the visiting goal. Instead it was home keeper Greg Fleming who was called into action to save an effort from Craig Sibbald.
The Bairns should have doubled their lead on the stroke of half-time when Lee Miller found himself clean through only to be thwarted by Fleming.
They went closer still on the hour when Baird’s curling effort rebounded from the far post.
At the other end Gary Harkins beat his man before shooting narrowly wide from the edge of the penalty area.
Falkirk hit woodwork for a second time when Craigen was denied his second by a post.
United almost grabbed a point in the closing stages when Andy O’Connell’s shot was well saved by Rogers.