The defender showed great composure when the ball dropped to him 10 yards out following a corner and sent a well-struck volley past Crawley goalkeeper Lewis Price from a tight angle.
It was tough on the visitors, who battled manfully to restrict their hosts and looked set for a point when they withstood some heavy pressure just before Ayling’s goal.
Crawley ‘keeper Price made brilliant first-half saves to deny Kieran Agard and Joe Bryan as City made most of the running.
The visitors were restricted to long-range efforts from Shaun Miller and Lanre Oyebanjo, but worked hard all over the park to limit the openings for their high-riding opponents.
City looked a threat at set-pieces with the height of Aden Flint and Matt Smith causing problems for the Crawley defence.
But John Gregory’s team competed for every ball and appeared crest-fallen at the final whistle.