Thistle travelled to Dunfermline to face bogey team Rosebank in round one of the Taylor Sullivan Funeral Directors Challenge Cup.
With 20 minutes Thistle opened the scoring when the combination of Munro and Barnes worked together and the latter fired home a powerful effort from just inside the box.
The goal seemed to inject some life into Rosebank as they started to turn the tide and only an excellent save from Wishart denied Mitchell minutes after the Thistle goal and the the keeper had to be alert to deny Wilkinson who had slipped away from Carson.
The halftime break allowed Thistle to regroup and they started the second half like the first and should have doubled their advantage minutes after the restart when Munro sent Barnes through on goal but with just the keeper to beat the striker fired his effort well over the bar.
Thistle introduced Petrie on the hour mark and just minutes after coming on he was involved in his side’s second goal when he forced McKinnon into an error with the ball breaking for Ireland who slammed home from just outside the box.
Midway through the half Jukes had a great chance to put the game out of sight as he found himself one on one but the midfielder was left with his head in his hands as his poor effort sailed well wide of target.
It was becoming a game of missed chances for Thistle and in the 73rd minute the normally prolific Barnes put in a contender for miss of the season when Cameron opened up the home defence before unselfishly cutting the ball across the face of goal to the unmarked Barnes who with the entire goal at his mercy somehow managed to miss the target.
With time running out Rosebank were beginning to push forward in numbers and only an excellent double save from Wishart avoided a nervy finish as he denied Kay then Mitchell with blocks to ensure Thistle progressed.