These ties always have banana skin potential so making it through was the main aim, rather than notching up a big win. We could have perhaps made things a bit easier for ourselves as it took until the last minute for the second to come, but that doesn't matter. What does is that we're in the last 16.
There were three changes to the side that drew with Dundee United on Saturday, Higdon coming in for Craig Dargo, Steven Thomson replacing Hugh Murray and Tom Brighton taking over from Garry Brady.
Both sides had a couple of chances in the early stages and Saints went in front after 25 minutes. A corner wasn't properly cleared and when David Barron crossed it back in, Higdon headed home his first goal for the club.
Paul Gallacher was needed to make a few saves before the break but Saints seemed to be in control at the start of the second half, Higdon having an effort cleared off the line and Thomson hitting the bar.
Ayr threatened on occasion but didn't trouble Gallacher too much and in the last few minutes had Dean Keenan sent off for a foul on Mehmet. With seconds to go, Mehmet was able to add the second after good work from sub Stephen O'Donnell to send Saints through.