Troon got us underway again in the second half, but it was Barrhead who were still asking the questions after the interval.
A lovely move came from a corner, with Fraser McLaughlin passing to Thomas McGoughey who then dummied to set up Anthony Etherson for the long range effort. The defender's effort was just a little too close to Cameron Taylor though, and the goalkeeper got down well to his right to make the save.
The game took a sour turn shortly after.
Midfielder Kieran O'Donahue came together in a 50-50 with Troon's Jordan Greenlees, and the Barrhead man came off second best, leaving him lying on the pitch in some distress. The referee stopped his watch at this point and after Barrhead's physio assessed the situation, an ambulance was called and O'Donahue was eventually stretchered off the park after a 30 minute delay. It was a very unfortunate incident and we wish Kieran all the best in getting back to playing again.
Barrhead weren't going to let the disruption affect their game plan though, and striker Brian Ashe was very unlucky not to get on the scoresheet after lobbing Cameron Taylor. Sean Vance did incredibly well to get back though and he cleared the ball off the line.
Within minutes though, Barrhead found themselves 3-0 up and out of sight of plucky Troon.
Danger man Thomas McGoughey was really troubling the Troon defence and showed some great flair to beat his man and send a cracking ball to the back post, where Jack Easdon was on hand to get his second of the game.
One of Troon's shining lights was creative midfielder Ross McCrea. He was probing the Barrhead defence and managed to pick out a good ball to Louis Kerr, but the attacker only managed to force a good save from Mark Parsons.
Barrhead found themselves four to the good before long, and it was that man Easdon again on the scoresheet wrapping up his hat-trick after a scramble in the box from another McGoughey ball.
Sam McNeill nearly put Barrhead five up with a fine effort from long range. Even finer though was the save, with Cameron Taylor doing incredibly well and showing great determination to tip the ball onto the top of the crossbar.
Troon had another opportunity with Christopher Vance finding Ross McCrea on the edge of the box, but McCrea was unlucky to see his shot fly just past the bottom left corner.
It was all too late though for Troon, and Barrhead deservedly march into the next round of the cup.