Ryan Donnelly's goal 11 minutes from time snatched Ayr a 1-0 win over 10-man Greenock Morton.
Ayr finished fourth last season in League One and showed why as a quick start gave Declan McManus the chance to fire them into an early lead but he pulled his shot wide from six yards.
Morton rued first-half chances as Conor Pepper, Ricki Lamie and McManus all spurned decent opportunities.
The Ton, who were relegated from the Scottish Championship last season, were reduced to 10 men in the 68th minute after Jordan Allan was dismissed for a dangerous challenge on Alan Forrest.
Ten minutes later, Donnelly's header into the bottom corner from close range put the home side into the lead following increased pressure. Peter McGill almost doubled their lead as he fired over the crossbar from inside the box and the visitors struggled to test Ayr in the final stages of the match.